The Mailing Industry and the United States Postal Service:
An Enduring Partnership

cross-written letter
Saving on Postage, 1839
Saving on Postage, 1839
Before postage rates were lowered in 1845, two sheets of paper cost twice as much to mail as one sheet. To save money on postage, some people cross-wrote their letters.

The mailing industry consists of all the organizations that communicate with customers and constituents through the U.S. Mail on a large scale — from direct marketers, to publishers, to nonprofits, to public entities — as well as all the businesses that help prepare mail, such as ad agencies, print shops, software vendors, and transportation providers. It's an industry that touches all of us, from the child receiving the first issue of his favorite magazine, to the busy adult receiving a sale flyer from a local store, to the retiree receiving a catalog of giving opportunities from her favorite charity. The total economic value of the mailing industry exceeded $1 trillion in 2015.

At the heart of the mailing industry is the U.S. Postal Service, which has delivered for America for more than two centuries. An explosion of mail in the late nineteenth and early twentieth century drove post offices and large-volume mailers to work together to handle mail more efficiently. Mailers used new methods of paying for postage which reduced mail handling by postal clerks and enabled the presorting of mail by destination, speeding dispatch and delivery. Mail volume continued to grow to such an extent that by the 1960s, it threatened to overwhelm post offices when deposited en masse by businesses at the end of each work day. This pushed the Post Office Department to embark on a concerted, nationwide campaign to enlist the aid of large mailers in leveling out the daily "mountains" of mail. So began a unique public-private partnership, unprecedented in scope and scale, which continues to this day.

Political Circular, 1848 (detail)
Political Circular, 1848 (detail)
Political Circular, 1848 (detail)
Circulars and handbills often promoted political and social causes. This circular was mailed in 1848 to organize supporters of the Free Soil Party, which opposed the extension of slavery into new U.S. territories.


The Growth of the Mail

The luxuries of one generation, become the necessities of the next.
Charles F. Jenkins, publisher, The Farm Journal, 19111

In the first half of the 1800s, the United States grew dramatically — stretching west to the Rocky Mountains after the Louisiana Purchase and to the Pacific coast by the 1840s. The U.S. Mail followed the frontier — by stagecoach, steamboat and rail. But while the postal network expanded, the cost to use it remained high. Most people rarely, if ever, mailed a letter. Merchants and other business professionals, who needed to keep in touch with customers and colleagues, were the most numerous paying users of the U.S. Mail — much of the mail consisted of newspapers and congressional documents that were delivered for free.2

In 1845, Congress slashed postage rates for letters and admitted "circulars and handbills or advertisements" into the mail at lower rates than letters, in an effort to reclaim revenue lost to private express companies, which proliferated in large cities following the development of reliable steam-powered transportation.3 Some private express companies transported mail between cities, while others delivered mail within cities — all were forbidden by law from competing with the U.S. Mail, although many did so. The number of letters in the U.S. Mail more than doubled after the 1845 postage rate cuts, increasing from an estimated 24.5 million in 1843, to 62 million just six years later. In 1851, Congress cut rates even further.

Preprinted Postal Card (back), 1882
Preprinted Postal Card (back), 1882
Preprinted Postal Card (front), 1882
Preprinted Postal Card (front), 1882
Preprinted Postal Card, 1882
Postal cards cost only a penny to post for most of the years from 1873 to 1952, versus two or three cents for a letter. By 1900, more than half a billion postal cards were issued annually. This postal card from Boston metalware dealers credited the account of E. Plouff & Son, tinsmiths, for the sale of a water pitcher in 1882.

In the second half of the 1800s, mail volume grew roughly sixteen times faster than the U.S. population. A number of factors contributed to growing mail volumes, including the introduction of new postal services, the lowering of postage rates, and the development of new products and services marketed to an increasingly savvy American consumer. One contributing factor was the introduction of government postal cards, which cost only a penny to post for most of the years from 1873 to 1952. Businesses purchased cards by the thousands and had them preprinted with advertisements or fill-in-the-blank messages, simplifying communications with customers and colleagues. The day after the first postal cards were issued in New York City in 1873, the city's postal clerks sold 200,000 in two and a half hours.

The development of the mail order industry around the same time also contributed to greater mail volumes. In 1872, Aaron Montgomery Ward, a former dry-goods salesman, produced his first single-page catalog. Two years later, his catalog had grown to 72 pages; by 1897, it was nearly 1,000 pages. Ward's success was matched by Sears, who overtook Ward in sales just three years later.

Free home delivery of mail in the countryside — called "rural free delivery" or RFD — further fueled the growth of the mail. Before the introduction of RFD in 1896, getting mail required a lengthy trip into town; RFD brought it directly to farms. Mail volume also climbed following the introduction of Parcel Post in 1913, which allowed heavier items to be mailed. Parcel Post electrified the mail order industry: Sears filled five times as many orders in 1913 as it did the year before. More mail created more mail, as catalogs, orders, and payments for orders also traveled by mail.

Meanwhile, cheaper paper and improved printing methods spurred the growth of periodicals; the number of newspapers increased from 5,871 in 1870, to 11,314 in 1880. Magazines also flourished — their numbers increased by 93 percent in the 1880s. In 1885, the postage rate for periodicals was slashed from two cents to a penny per pound, which meant that most periodicals were delivered for a mere fraction of a cent. Advertising took off in periodicals — the number of ads in Harper's Magazine increased more than twentyfold between 1882 and 1890, from 15 to 348. The sale of advertisements boosted publishers’ profits, putting more and more magazines into the mail.

Delivering Parcels, 1921
Delivering Parcels, 1921
Delivering Parcels, 1921
New services like rural free delivery and Parcel Post, cheap postage rates for periodicals, and the growing popularity of mail order contributed to mail volume increases.

Many advertisers preferred to mail information to potential customers or supporters directly, especially when targeting a select audience. Direct mail could be sent to a select group of people who, if not already customers or supporters, were likely to become so. Advertisements didn't just promote goods and services — they also promoted political candidates, political party platforms, and social and charitable organizations and causes. In the 1880s, typewriters and duplicating machines made it possible to cheaply produce dozens or hundreds of copies of printed pages. Mail service providers emerged to assist advertisers with especially large mailings. Some print shops expanded into mailing services, while mail shops sprang up that specialized in addressing and sending out large mailings. Letter shops designed, created, addressed, and mailed items. Mailing list brokers, meanwhile, supplied lists of names and addresses of prospective customers.

The success of a direct mailing hinged on reaching the right people by using an accurate mailing list. Mailing lists required regular maintenance, because every year some addressees moved, changed their names, or died. Beginning in the 1920s, postmasters were required to correct mailing lists upon the request of the list owners, for a small fee, and were also directed to correct single addresses if mailers had printed a pledge on the mailpiece stating that they would pay for the service.

MAIL CLASSES:
In 1863, mail was divided into three classes:
 letters, called First-Class Mail;
 newspapers and other periodicals, called second-class mail; and
 all other mailable matter, called thirdclass mail.
In 1879, miscellaneous printed matter, like advertisements and circulars, remained in the third class, while merchandise and other mailable matter shifted to a new fourth class. In 1996, the name of second-class mail changed to Periodicals, third-class mail changed to Standard Mail (A), and fourthclass mail changed to Standard Mail (B). In 2001, Standard Mail (A) was shortened to Standard Mail, while Standard Mail (B) became Package Services.

Simplified addressing, which let mailers reach every addressee in a community without having to keep an up-to-date mailing list, was introduced for third-class mail delivered along rural routes in 1923; in 1927 it was extended to post office box holders at post offices not having city delivery. Instead of labeling each piece of mail with a specific name and address, mailers could simply deposit enough pieces for a carrier route or post office box section, addressed, for example, "Box holder, Route 1, Bristol, Tenn." This was easier for mailers and also saved the Post Office Department time and money because clerks and carriers did not have to sort each piece — they merely left one in each mailbox.4

In 1928, Congress created a new “bulk rate” category for third-class mail, with rates calculated by the pound rather than by the piece. To qualify for the lower bulk rate, mailers were required to sort and bundle a minimum number of pounds or pieces of mail into state and city destinations before bringing it to the post office. Mailers often saved money by hiring a mail shop or letter shop to do this work for them.

Also in 1928, Congress authorized Business Reply Mail, which provided an easy way for businesses to boost customer response rates. Business Reply Mail allowed businesses to include a reply card or envelope in the mailing, which the recipient could return postage-free — businesses paid the postage, plus a return fee, only for pieces that were actually returned.

Lorem ipsum
Delivering Mail, 1923
Delivering Mail, 1923
In the 1920s, the Post Office Department introduced simplified addressing for rural addresses, address correction services, lower bulk postage rates for third-class mail, and Business Reply Mail, making it easier for American companies to conduct business by mail.

Large-Volume Mailers Help Handle Heaps of Mail

No longer need office boys suffer from impediments of speech because of mucilage coated tongues from licking postage stamps. … In increasing numbers the large business houses … are discarding the stamp … in favor of rapidly running machines which, at one operation, seal, impress a permit number approved by postal authorities, cancel and count the letters or circulars that are fed into them.
Post Office Department, 19225

In the early 1900s, mail growth continued to outpace population growth. Mail volume more than doubled from 1900 to 1910, rising from about 7 billion to 15 billion pieces. About half of all mail originated in just a handful of cities, congesting already-crowded urban facilities.6 Post office personnel struggled to sort and deliver ever-growing volumes of mail with limited staff and space. The introduction of precanceled stamps, mailing permits, and postage meters helped speed delivery by reducing the number of times that large mailings needed to be handled. Mailers who used these time-saving methods of paying for postage were also expected to comply with "all reasonable requests" of postmasters for presorting their mail "into States, counties, cities, etc."7 In some cases this mail could be taken directly to mail trains for dispatch.

Beginning in 1901, Chicago firms that mailed more than 10,000 pieces a week could use precanceled postage stamps for third- and fourth-class mail.8 Mailers in other cities could also request permission to use precanceled stamps, which were permitted on First-Class Mail beginning in 1924. Mail with precanceled stamps bypassed facing and canceling at the post office, saving postal clerks hours of labor. "Facing" mail — orienting each piece to put the stamps in the same relative position — and canceling mail — postmarking each piece and marking through stamps to prevent their reuse — were time-consuming tasks. In the Chicago Post Office, canceling mail was so time-consuming that in 1914 Thomas F. Flaherty, secretary of the National Federation of Postal Clerks, called for all mail order firms to use only precanceled stamp on their catalogs. In its monthly magazine, The Union Postal Clerk, the federation noted that "a clerk working industriously for eight hours could cancel the stamps on not more than 5,000 packages," and complained of “a period of protracted overtime in the Chicago Post Office” and of the “suffering and hardship” imposed on clerks by “the annual reign of terror” which was the spring catalog mailing season.9

Precanceled stamp on envelope mailed circa 1950.
Precanceled stamp on envelope mailed circa 1950.
Mailing permit imprint on envelope mailed circa 1920.
Mailing permit imprint on envelope mailed circa 1920.
Postage meter imprint on envelope mailed in 1963.
Postage meter imprint on envelope mailed in 1963.
Postage Paid by Precanceled Stamp, Mailing Permit Imprint, and Postage Meter Imprint
Precanceled stamps, mailing permits and postage meters made it easier to pay for and process large amounts of mail.
Top: Precanceled stamp on envelope mailed circa 1950.
Middle: Mailing permit imprint on envelope mailed circa 1920.
Bottom: Postage meter imprint on envelope mailed in 1963.

Mailing permits, first authorized in 1904, eliminated the need for stamps altogether. In lieu of a stamp, the word “Paid” was printed in the upper right corner of the envelope along with the permit number and the city of mailing. Mailers brought a minimum number of permit-imprinted identical pieces of third- or fourth-class mail directly to the post office, for mailing. Because each piece of mail was identical, postal clerks could weigh all the sacks of mail and then divide the total by the weight of a single piece to determine the total number of pieces; they multiplied this number by the postage rate to determine the amount of postage to be collected for that particular mailing. Mailing permits relieved mailers of the need to apply stamps to each piece, and spared postal clerks the need to cancel and postmark the mail. Beginning in 1920, postage for identical pieces of First-Class Mail could also be paid via permit imprints; most pieces of First-Class Mail, however, varied slightly in weight.

Postage meters — first tested by inventor Arthur Pitney in 1903 and authorized for use in 1920 — provided mailers with a means of stamping and counting, piece by piece, large amounts of non-identical First-Class Mail. Postage meters printed the name of the post office, date of mailing, and amount of postage on each piece of mail. The meters were developed and maintained by private companies — the largest was the Pitney-Bowes Postage Meter Company — which leased the machines to individual mailers. Mailers took their leased postage meters to the post office, as needed, where authorized postal employees "set" the meters for a certain amount of postage, upon advance payment by the mailer. Postal employees sealed the unit, so it could not be tampered with, and the unit automatically locked when all the prepaid postage had been used.

Precanceled stamps, mailing permits and postage meters made it easier for businesses to send large amounts of mail, and easier for post offices to deliver it. Although mail volume dipped during the Depression, it recovered during World War II and swelled to unprecedented heights in the postwar economic boom.

CARE Worker with Mailed Donations, 1963
CARE Worker with Mailed Donations, 1963
CARE Worker with Mailed Donations, 1963
In 1952, Congress authorized lower postage rates for mail sent by nonprofit organizations, making it easier for charitable organizations to fund their missions. CARE was established in 1945 to fight global poverty.

1960s: Reaching out to Industry to Level Mountains of Mail

For a long, long time prior to 1960 no one at [postal] headquarters was willing to listen to business mailers. All of that has changed. Harry J. Maginnis, President, Associated Third Class Mail Users, 196510

Between 1940 and 1960, mail volume more than doubled, from 27.7 billion to 63.7 billion pieces mailed each year. The development of the computer brought centralization of accounts and sent a growing mass of bills and payments, bank deposits and receipts, and credit card transactions through the mail, while the number of advertisements and magazines in the mail continued to climb. Most mail was generated by businesses and was largely First-Class Mail; by long tradition, most businesses deposited their mail at the end of each workday.

"Your Post Office Department is daily overwhelmed by a 5:00 p.m. Mountain of Mail," First Assistant Postmaster General Fred Belen told a group of Chicago mailers in June 1961, "the growing volume of mail has … seriously strained the Post Office facilities."11 The next month, Postmaster General Edward Day told a group of New York mailers that the "daily logjam has cut down on our efficiency, slowed our drive for greater economy in postal operations, and played havoc with our efforts to improve mail service generally."12

In the summer of 1961, Department officials began a concerted campaign to enlist the cooperation of large mailers in the Nationwide Improved Mail Service program, or NIMS. The initial focus of NIMS was to encourage mailers to deposit mail earlier in the day or in staggered increments. The need to balance workload was made even more urgent by the increased use of mechanization. Employees could be shifted to meet hourly fluctuations of mail, but machines could not.

Comedian Marty Allen With Charge Cards,
1960
Comedian Marty Allen With Charge Cards, 1960
Comedian Marty Allen With Charge Cards, 1960
Financial industries depended on the mail to conduct business, including the management of two new financial products that emerged in the mid-1900s: charge cards and credit cards. Diners Club issued the first general purpose charge card in 1949. Banks began issuing general purpose credit cards in the 1950s. The first two national bank credit cards — today's VISA and MasterCard — were introduced in the late 1960s.

Belen explained:

Early in the day there is plenty of dock space at the post office so that there are not long delays in unloading your mail. The conveyors, canceling machines, and sorting cases are available early in the day for the prompt processing and dispatching of your mail.  After 5 o'clock these facilities are so crowded that your mail must take its turn. Unfortunately, its turn may not come until after it has missed the dispatch you intended to make.13

Delivery Zones
During World War II, thousands of experienced postal employees left to serve with the military. In 1943, the Post Office Department began using zone codes in 124 large cities, so that mail could be sorted by employees who did not have detailed scheme knowledge. Under this system, delivery zones were identified by one or two numbers between the city and state — for example, Birmingham 7, Alabama. Zone codes were used in 131 cities in total; most continued to use zone codes until ZIP Codes came along in 1963.

ZONE ALL MAIL flyer
ZONE ALL MAIL flyer
ZONE ALL MAIL flyer

Belen also asked mailers to sort their mail more finely — if possible, by delivery zone or carrier route. Large-volume mailers saved the Department more than a million manhours a year by bundling mail to delivery zones, but there was room for improvement since only about 34 percent of second-class mail and 23 percent of third-class mail was sorted this way. Although the Post Office Department didn't give mailers a direct financial incentive for this additional sorting, mailers received an important side benefit — speedier deliveries. This was a compelling reason for many mailers. Charles Pace, circulation manager for the Wall Street Journal in the 1960s, recalled that "we always spoke of minutes, not hours, when dispatching mail."14 Equally compelling to many mailers — saving the Department time helped curb spiraling labor costs, which in turn helped rein in postage rate increases.

Lorem ipsum
Mail Flow Diagram, 1968
Mail Flow Diagram, 1968
Bulk mail skipped nearly half of the handling steps shown in this 1968 mail flow diagram. Post offices received bulk mailings already sorted, bundled, sacked, and ready for dispatch.

To support NIMS, Mail Users Councils (later called Postal Customer Councils) were established in hundreds of large cities, providing a regular forum for mailers and postal officials to discuss service improvement. In a July 1961 speech to the New York council, Day stated:

The NIMS program … represents the opening phase of what we hope will be a lasting era of cooperation between the Post Office Department and the business community. … Over the long haul, we intend to ask for your advice and recommendations, from time to time, concerning other matters involving improved mail service. We want your help. We need your support.15

Just two years after the start of NIMS, the percentage of after-five First-Class Mail dropped from 75 percent to about 55 percent.

Balancing the workload helped, but it was not enough. To cope with rising mail volumes, the Department also needed to work more efficiently. Adding more employees to sort ever-increasing amounts of mail was not an option — costs aside, there was nowhere to put them, as many large postal facilities were already outdated and cramped.

Excerpt from "Postmaster's ZIP Code Promotion Kit," March 1966.
Excerpt from "Postmaster's ZIP Code Promotion Kit," March 1966.
Excerpt from Publication 69, "A New Look at ZIP Code," July 1971.
Excerpt from Publication 69, "A New Look at ZIP Code," July 1971.
ZIP Code Promotional Material
The Post Office Department published a wide variety of promotional material to encourage the use of ZIP Codes.
Top: Excerpt from "Postmaster's ZIP Code Promotion Kit," March 1966.
Bottom: Excerpt from Publication 69, "A New Look at ZIP Code," July 1971.

Numbering the Nation

ZIP Code is the only thing making possible the continued operation of the Post Office Department.  
Howard Russell, President, Russell Distributing Company, 196716

In 1962, following the recommendation of the presidentially appointed Advisory Board of the Post Office Department, the Department developed a numeric address coding system. By its launch in July 1963, the Department had assigned a five-digit “ZIP Code” to every address in the nation. The ZIP Code helped postal employees manually sort mail by consolidating regional, city, and state information into five easy-to-read numbers — previously, clerks had to memorize the names and locations of thousands of post offices in order to sort mail to the right hub.  The code also enabled computerized presorting of mail by large-volume mailers, who could then bundle and deposit mail sorted by sectional center, speeding delivery by eliminating multiple handlings. The ZIP Code also paved the way for the development of automated mail processing.

 At first the use of the ZIP Code was voluntary. In partnership with the mailing industry, the Department embarked on an ambitious promotional campaign to encourage Americans to use ZIP Codes. Since about 80 percent of all mail was generated by businesses, the Department also depended on the cooperation of large-volume mailers to use the new code. To hasten the code's adoption, beginning in 1967, second- and third-class bulk mail had to be presorted by ZIP Code to qualify for discounted postage rates.

First Issue of Memo to Mailers, 1966
First Issue of Memo to Mailers, 1966
First Issue of Memo to Mailers, 1966
The Postal Service published Memo to Mailers from August 1966 through December 2006, when it was replaced by MailPro.

To help implement the ZIP Code, and to develop and implement other service improvements, the Department opened several new channels of communication with major mailers. In 1965, the Mailers' Technical Advisory Committee (MTAC) was created, consisting of representatives from mailing associations and other segments of the mailing industry, like envelope manufacturers and printers. MTAC advised postal officials on how proposed new processes and equipment might affect the nation’s largest mailers and also helped identify and test possible improvements.

In 1966, the Post Office Department launched Memo to Mailers, a monthly newsletter that showcased best mailing practices and business success stories, and was peppered with practical tips for efficient mailing. In the first issue, Postmaster General Larry O'Brien called it a "newsletter to advance mailers' interests," referring to mailers as the Postal Service’s “partners" in providing "the American people with the best possible mail service."17

In 1967, the Department hosted the first National Postal Forum, a two-day series of moderated panel discussions on topics affecting large-volume mailers, from “Why Presort When You Don't Have To?“ to "Mailing Needs of the Publishing Industry." The first forum was attended by about 2,300 mailers and postal officials. Regularly-held forums served as venues for mailers to discuss recommended service improvements with postal officials, to offer constructive criticism on postal policies and programs, and to learn about new postal initiatives and operational changes.

Educational Outreach, 1970
Educational Outreach, 1970
Educational Outreach, 1970
The Postal Service educated mailers in best mailing practices, including how not to design mail. A 1970 issue of Memo to Mailers pictured "the violators," from "Mack the Moose" (oversized envelope) to "Loose Lipped Louie" (incompletely sealed envelope).

The increasing use of the ZIP Code and the Post Office Department's closer partnership with the mailing industry helped the mail flow, but growing volumes of mail and the lack of money to modernize postal facilities and operations continued to threaten efficient mail delivery. Low wages of postal employees led to high turnover, which also stymied the postal system. In 1968, the presidentially appointed Commission on Postal Reorganization, chaired by AT&T’s Frederick R. Kappel, recommended that the Post Office Department be converted into a self-supporting, government-owned corporation, with the ability to borrow money to finance postal buildings and mechanization. In 1970, Congress passed the Postal Reorganization Act, transforming the Post Office Department into the United States Postal Service, a self-supporting establishment of the U.S. Government with more authority over its own operations. The new Postal Service officially began operations on July 1, 1971.

1970–2000: Improving Productivity and Service

A growing, productive Postal Service is in the interest of every stakeholder,
whether he or she mails a dozen, or tens of millions, of pieces annually

The Blue Ribbon Committee of the Postal Service, 199718

Mail volume continued to rise throughout the twentieth century, increasing from about 85 billion pieces in 1970 to nearly 208 billion pieces in 2000. At the same time, the Postal Service's delivery network increased — by 17.5 million addresses in 1990–2000 alone. The Postal Service worked continuously to improve service and control costs, about 80 percent of which were tied to labor. The Postal Service was able to deliver 145 percent more mail in 2000 versus 1970, with only about 22 percent more employees, largely due to automation and mailers' cooperation in producing automation-compatible mail and their participation in worksharing. The Postal Service also worked with the mailing industry to reduce the amount of costly undeliverable-as-addressed mail and to ease mail entry and payment. Special MTAC work groups were formed as needed to study particular areas for improvement (see "MTAC Work Groups").

Postmarks on Letters Mailed for Local and Out-of-Town Delivery, 2015
Postmarks on Letters Mailed for Local and Out-of-Town Delivery, 2015
Postmarks on Letters Mailed for Local and Out-of-Town Delivery, 2015
Since area mail processing was introduced in the 1970s, most postmarking has occurred at large mail processing facilities. Names of small towns continued to appear in postmarks on some locally-delivered mail or if specially requested at the post office.
Top: Postmark on letter mailed at Nokesville, Virginia, for local delivery.
Bottom: Postmark on letter mailed at Nokesville, Virginia, for out-of-town delivery.

Automation and Worksharing: In the 1970s, the Postal Service changed its mail processing network to facilitate automated mail processing. "Area mail processing" — funneling non-local mail from small cities and towns to a nearby central mail processing facility — enabled the concentrated deployment of costly automated mail sorting equipment. The Postal Service also developed a separate Bulk Mail Network to speed handling of parcels and bulk third-class mail, which had traditionally been given "non-preferential" treatment in post offices.

The first worksharing discount was introduced in 1976, when mailers received a one-cent discount for presorting First-Class Mail by ZIP Code, which is what the Postal Service saved by not having to sort this mail. In the next few years, the Postal Service worked with mailers to increase presorting, making more than a dozen rule changes suggested by mailers to increase their participation. In 1978, second-class bulk mailers became eligible for discounted rates if they presorted periodicals to the 5-digit or carrier route level. In 1979, a discount for third-class mail presorted to the carrier route was introduced.  And in 1981, mailers became eligible for a "5-digit presort" discount if they presorted a minimum amount of third-class mail by ZIP Code, or First-Class Mail by carrier route.19

As the Postal Service deployed more automated machinery, it offered discounts to mailers who maximized the compatibility of their mail with increasingly sophisticated mail sorting equipment — first by including the ZIP+4 code in addresses, and later by pre-barcoding mail. In 1982, the first computer-driven single-line optical character reader (OCR) was deployed, which could read addresses and print barcodes on envelopes representing the ZIP Code, enabling letters to be automatically sorted to the correct delivery office. In 1983, the Postal Service introduced the ZIP+4 code, which added a hyphen and four digits to the existing five-digit ZIP Code. The four extra digits routed mail to one floor of an office building, one side of a block, or specific post office boxes, enabling letters to be automatically sorted to the correct carrier at the delivery office. In 1983, discounts for First-Class Mail bearing the ZIP+4 code were approved. In 1988, mailers received a discounted rate for third-class mail bearing ZIP+4 codes; both First-Class Mail and third-class mail were given even greater discounts if the mail was pre-barcoded. Mailers who pre-barcoded third-class letters, and sorted their mail to three digits, became eligible for discounts in 1991. Later in the 1990s, discounts were introduced for pre-barcoding flats and parcels.

FLAT::
Not just the opposite of round. Flats include magazines, newspapers, catalogs, booklets, and large envelopes.

Educational Outreach, 2000
Educational Outreach, 2000
Educational Outreach, 2000
The Postal Service educated mailers in how to prepare mail that qualified for discounts. A free "mailpiece quality control" course was advertised in the January 2000 issue of Memo to Mailers.

To help teach mailers how to qualify for discounted "automation" postage rates, the Postal Service increased its educational outreach. "Automation readability specialists" helped mailers design automation-compatible mail, the New York Post Office operated a Mailer Education Center, while "Operation MAIL" helped customers identify problems with their mailings. In the 1990s, the Postal Service operated 25 Postal Business Centers staffed by specialists who helped small- and medium-sized mailers qualify for automation rates. The Postal Service also provided classes in mail preparation at Bulk Mail Entry Units, and in 1997 created a "Mailpiece Quality Control Training Program" for mailers.

Worksharing and automated letter sorting increased postal productivity between 1980 and 1990 — raising the average amount of mail delivered per employee from 159,435 to 197,202 pieces per year — but opportunities for improvement remained. Due to surging mail volume, letter carriers were spending more time in the office sorting mail into delivery order. In 1990, the Postal Service expanded the delivery barcode by two more digits, containing exact address information. This "delivery point barcode" enabled letters to be automatically sorted into delivery sequence, which helped reduce carriers' office time.

Feeding Letters into a Delivery Barcode Sorter, 2007
Feeding Letters into a Delivery Barcode Sorter, 2007
Feeding Letters into a Delivery Barcode Sorter, 2007
Delivery barcode sorters, deployed in the 1990s, automatically sorted letters into delivery order. Expanded ZIP Code information, pinpointing addresses, was encoded in barcodes printed on envelopes. The Postal Service offered discounts to bulk mailers who pre-barcoded their mail, saving the Postal Service time and money.

Beginning in 1985, postage rates for periodicals were discounted for mail entered into the postal system closer to the delivery office. In 1991, third-class mail became eligible for such "drop ship" discounts. The Postal Service saved money on mail processing and transportation when mailings were entered into the system closer to the point of delivery and passed along these savings to mailers. In addition to lower postage rates, drop shipments gave mailers greater control over the timing of deliveries.

Worksharing activities saved the Postal Service an estimated $15.3 billion in 1999 alone — nearly one quarter of its operating costs.20 By January 2001, mailers received postage discounts ranging from 6 to 63 percent, depending on the amount of mail preparation, handling, and transportation they provided.21

Accepting Drop Shipped Mail, 2006
Accepting Drop Shipped Mail, 2006
Accepting Drop Shipped Mail, 2006
Mailers have received discounted rates for transporting periodicals closer to their point of delivery — called "drop shipping" — since 1985. Standard Mail became eligible for such discounts in 1991.

Address Quality: The Postal Service also continued to work with mailers to reduce the extra work and costs associated with undeliverable-as-addressed mail. Beginning in 1973, the address line "John Doe (or current occupant)" was tested on bulk third-class catalogs and tabloids; it became a permanent option in 1976. Previously, most undeliverable catalogs were discarded if the addressee had moved.

In 1974, a centralized address correction system was introduced at post offices. Instead of each letter carrier maintaining address files and individually re-addressing letters for customers no longer on their routes, post offices maintained a central file of address corrections, with corrections made by a clerk. Just three years later, this manual process began to be automated. In 1985, the Postal Service introduced Address Change Service (ACS) for periodicals, providing publishers with subscribers' change-of-address information on a magnetic tape on a weekly or monthly basis. This electronic service automated and accelerated corrections. The year it was introduced, the deputy director of corporate distribution for The Reader's Digest noted that ACS "more than halved the number of … wasted and destroyed copies" of its magazine and "minimized the number of issues forwarded."22 Most importantly, he noted that it helped retain customers. ACS expanded to third-class mail in 1989, and to First-Class Mail and fourth-class mail in 1990.

In 1986, the National Change of Address (NCOA) program was launched — its database contained 36 months of permanent change-of-address orders filed with the Postal Service. NCOA operated through licensed vendors who provided address-matching services to mailers, letting them update their mailing lists all at once, before a mailing, versus one correction at a time after the mailing was sent. One mail service provider noted that NCOA provided corrections within two weeks, versus one to eighteen months. This was a win-win for mailers and the Postal Service — mailers got more pieces delivered, and the Postal Service avoided the costs of re-handling undeliverable mail. A marketing manager at Talbots calculated that his firm saved $35,000 just on its first NCOA mailing. Previously, Talbots typically received 60,000 address corrections at $1 each after each mailing. Using NCOA service cost his company $15,000, but it corrected 50,000 addresses in advance — both saving the company money and enabling delivery of the catalog to customers who had moved.

Americans ON THE MOVE
12 percent of Americans change addresses annually.
 37 million people move each year.
 The average American moves 11 times in a lifetime.
 The Postal Service processed more than 34 million changes of address in 2014.

In 1987, the Postal Service introduced the Coding Accuracy Support System (CASS), designed in cooperation with the mailing industry, to verify the accuracy of ZIP Codes in mailers' address-matching software programs. In 1993, Address Element Correction (AEC) was introduced, which evaluated addresses that could not be resolved by address-matching software. And in 1996, the Postal Service introduced FASTforward, a subset of the NCOA database containing the most recent five months of change-of-address information. Licensees could process mailpieces through FASTforward-equipped optical character readers, which printed correct barcodes and updated address information on mailpieces with outdated addresses on-the-fly during processing.

Ad Hoc Advisory Committees

Postmasters General appointed special advisory committees, consisting of top mailing industry and Postal Service officials, to provide strategic direction and recommendations.

In 1996, Postmaster General Marvin Runyon appointed the "Blue Ribbon Committee" of industry and postal officials to identify opportunities for growth, service improvement, innovation, accountability and productivity. The committee, which included the CEOs of Fingerhut and ADVO, the president of L.L. Bean, a vice president of AT&T, and the Postal Service's Chief Operating Officer, issued its report, "Finding Common Ground," in 1997.

In 2001, Postmaster General William Henderson created the Mailing Industry Task Force, to recommend ways to enhance the value of mail in the increasingly competitive communications marketplace.

Participation in ACS, NCOA, or FASTforward satisfied the Postal Service's Move Update standard, which required addresses on presorted and automation rate First-Class Mail to have been updated within six months of a mailing beginning in 1997. In 2008, the Move Update standard also applied to Standard Mail (previously called "third-class mail") and required that addresses be updated within 95 days of mailing. Move Update standards helped reduce the amount of undeliverable-as-addressed mail, most of which was caused by address changes when people moved. Sometimes addresses changed even if people didn't move. In the 1990s, when many rural route addresses changed to street-style addresses as part of the implementation of Emergency 9-1-1 Response systems, the Postal Service developed the Locatable Address Conversion System (LACS) database to provide information on address changes due to 911 conversions and street renamings.

Customer Experience: In 1983, the USPS began referring to second- and third-class mail as "Bulk Business Mail," versus the older term "non-preferential mail." Postmaster General William Bolger explained that the older term was "not at all consistent with the volume, revenue, and important growth represented by Bulk Business Mail and our relationship with its mailers."23 By 1981, third-class mail had grown to represent more than 30 percent of mail volume, and it continued to grow briskly in the 1980s — increasing by more than 18 percent in 1984 alone.

Moving Palletized Mail, 2001
Moving Palletized Mail, 2001
Moving Palletized Mail, 2001
Mailers began using trays and pallets to help transport mail in the 1970s. One pallet could hold as much mail as 25 to 50 sacks, reducing handling time.

The Postal Service and the mailing industry worked together to improve postage payment and mail entry processes. Beginning in 1979, mailers no longer needed to lease a postage meter for each post office where they entered mail — instead, one could be used to pay for mail deposited at multiple post offices. In 1988, the Postal Service introduced the Manifest Postage Payment System, which let mailers pay for bulk shipments of variable-weight mail of the same class and category (letter, flat, or parcel) via permit imprint, making it easier for mailers to qualify for bulk rates. Also in 1988, following a successful pilot with the publisher of Newsweek, the Postal Service let publishers pay for postage from a centralized postage account, rather than maintaining separate accounts at every postal facility where they entered mail — in the case of Newsweek, more than 30.24 In 1994, all large mailers were given the ability to pay centrally for mailings entered at multiple sites.

In 1995, the Postal Service introduced the ADVANCE system, which enabled mailers to electronically notify facilities that mail was coming and select a desired delivery date. In 1997, Direct Link was tested, which took some of the paperwork out of bulk mail entry via electronic data transfers. In 1998, the Postal Service tested the Mailing, Evaluation, Readability and Lookup Instrument (MERLIN), which helped speed mail entry by automating several mail acceptance tasks, from checking presort accuracy, to counting pieces, to validating postage. In 1999, PostalOne! was tested, and Entry Schedule for Periodicals (ESP) went online, providing arrival times of mailings at plants. Also in 1999, a new web-based Drop Shipment Appointment System (DSAS) was introduced; it replaced an older electronic system and featured enhanced capabilities suggested by a special MTAC work group.

MTAC Work Groups

Since its creation in 1965, the Mailers' Technical Advisory Committee (MTAC) has provided technical advice and feedback vital to the formation and implementation of many postal innovations. Special MTAC task forces and work groups have been formed as needed to study particular areas for improvement. For example:

► In 1978, the Alternate Delivery Systems task force was created to find ways to streamline postal business practices and regulations, to help keep major customers from switching to private delivery of second-, third-, and special-rate fourth-class mail. By June 1980, the Postal Service had implemented nearly 30 of its 75 suggestions, such as permitting publishers to combine different titles in the same sack to qualify for presort rates and accepting smaller shipments at bulk mail centers.

► In 1988, the Worksharing Project Work Group was formed, which identified 36 costsaving opportunities. Six were implemented by August 1989, including transitioning to a certification system for bulk mailers, providing free audits of customer mailing lists, and extending Address Change Service (ACS) to third-class bulk mail. The Automation Bar Code Group, formed the same year, identified challenges and opportunities in automating the mailstream.

► In 1992, MTAC's Competitive Services Task Force made 183 recommendations for service improvement, including the standardization of bulk mail preparation, regardless of class or rate.

In the early 1970s, mailers began switching to trays and pallets instead of sacks. In 1974, following a successful pilot test with firms like R.R. Donnelly & Son and McCalls, the Postal Service began providing reusable wooden pallets, instead of sacks, to large mailers upon request, to expedite mail handling. One pallet could be handled as a unit and could hold as much mail as 25 to 50 sacks, which reduced handling time and the risk of damage. Beginning in 1986, mailers were allowed to commingle third-class bulk mail prepared at different rate levels (basic, five-digit, and carrier route) on the same pallet.

The Increasing Pace of Change: Innovation in the 21st Century

Never before has the preparation, processing and delivery of mail been changing so rapidly.                            
United States Postal Service, 200125

The new century presented new challenges. After decades of growth, mail volume began to fall in 2007, reducing revenue. The Postal Service relied almost exclusively on revenue from postage to fulfill its mission — delivering affordable, universal service to a constantly expanding delivery network. The Postal Service's close partnership with large-volume mailers became even more important as it worked to improve service, manage costs, and grow revenue in an increasingly competitive business environment.

To help keep advertising mail relevant in the multichannel advertising universe, the Postal Service introduced a number of innovations in the early 2000s. Starting in 2003, repositionable sticky notes could be attached to envelopes, calling attention to products, services and company contact information, and inviting customers to look inside. That same year, the Postal Service introduced Customized MarketMail, which enabled advertisers to mail pieces of virtually any design and shape, and also signed its first negotiated service agreement with a major mailer, offering pricing incentives in exchange for increased use of the mail. In 2009, the Postal Service began offering "summer sales" for Standard Mail volumes above a certain threshold as well as "saturation mail volume" pricing incentives. In 2011, the Postal Service introduced “Every Door Direct Mail” (EDDM), which allowed bulk mailings to be addressed simply to "Postal Customer," regardless of which sort of delivery route customers lived on. The Postal Service also introduced discounts to encourage use of the mail. In 2011, it offered the Reply Rides Free promotion to encourage the inclusion of marketing messages in bill and statement mailings; the next year, it began the 2nd Ounce Free promotion. Beginning in 2011, the Postal Service also offered limited-time postage discounts or credits to mailers who integrated interactive digital technologies like QR codes onto their mail.

Scanning a pallet of Standard Mail, 2006.
Scanning a pallet of Standard Mail, 2006.
Scanning a Priority Mail package, 2014.
Scanning a Priority Mail package, 2014.
Scanning Barcodes to Track Mail
By scanning barcodes on mail — whether by hand or using automated equipment — the Postal Service could provide mailers with detailed information on where and when their mail was processed and delivered.
Top: Scanning a pallet of Standard Mail, 2006.
Bottom: Scanning a Priority Mail package, 2014.

In 2003, the Postal Service launched Parcel Return Service, which enabled participating merchants to save on postage on returned merchandise. Consumers could return packages without paying postage by using a prepaid return label addressed to the nearest post office or bulk mail center, where the merchant or his agent picked the package up. The Postal Service also expanded Parcel Select service, completing the "last mile" of delivery for parcel consolidators and private carriers. Private carriers relied on the Postal Service for the "last mile" delivery of packages in less-populated areas, where they could not deliver packages profitably. This helped both the private carriers and the Postal Service, which under its universal service mission, delivered to even the most remote areas on its daily rounds. The first private carrier to ally with the Postal Service in this hybrid service was Airborne Express, in 1999.  UPS followed in 2003, and FedEx came on board in 2004; both increasingly relied on the Postal Service to deliver packages the "last mile."

Because the ability to track mail was important to large-volume mailers, in 1999 the Postal Service launched Delivery Confirmation service, providing the date, time, and ZIP Code of delivery for Priority Mail and parcels to customers either online or via a toll-free number. In 2002, the Postal Service officially launched Confirm service, which provided tracking information to participating mailers via an identifying “PLANET” barcode printed on their mail. To enable even greater mail tracking, in 2006 the Postal Service introduced a new “Intelligent Mail barcode,” with four vertical bar types rather than two. It encoded almost three times more information than previous codes, consolidating information from both the POSTNET (routing) and PLANET (tracking) barcodes, with room for other services in the future. Confirm service subscribers and ACS users were given the option of using the new barcode in 2006. It became optional for large-volume mailers in 2009, and by 2010 about 30 percent of business mail contained Intelligent Mail barcodes. To hasten the adoption of the Intelligent Mail barcode, mailers were required to use it for automation price eligibility beginning in 2013.

POSTNET Barcode
POSTNET Barcode
POSTNET Barcode
With barcodes, mail can be sorted automatically. The first postal barcode, the POSTNET barcode, was introduced in 1982 and converted 5-diget ZIP Codes to a machine-readable format. In 1983, the ZIP+4 code expanded the barcode to nine digits. In 1990, the barcode expanded again when the Postal Service added two more digits with exact address information.

Intelligent Mail Barcode
Intelligent Mail Barcode
Intelligent Mail Barcode
The Intelligent Mail barcode (IMb) was launched in 2006. The IMb can hold nearly triple the data of the POSTNET barcode — not just the delivery address, but also the sender's address, the mailpiece information, and information on extra services. In 2013, large mailers were required to use the IMb to qualify for postage discounts.

The Internet enabled additional innovations. NCOALink and LACSLink helped mailers update their address files. Electronic Merchandise Return Service allowed customers to download pre-paid return labels from retailers’ websites. Postage-paid information-based indicia became available through licensed vendors like stamps.com, Click-N-Ship let customers print and pay for shipping labels for packages online, emailed delivery notification was provided to Track and Confirm customers, and emailed Return Receipts were available upon request. The website mailtracking.usps.com became a one-stop shop for business customers to access tracking information, while ribbs.usps.gov/mtac and usps.com/nationalpcc helped keep business customers informed of the latest postal policies and initiatives.

Postal Explorer homepage
Postal Explorer, 2015
Postal Explorer, 2015
Postal Explorer, online at pe.usps.gov since 1998, provides access to postal information and tools, from mail manuals and service guides, to rate calculators and zone charts.

The Postal Service also continued to streamline its mail acceptance procedures. In 2000, Standardized Acceptance and Verification (SAVE) procedures were introduced for First-Class Mail and Standard Mail. PostalOne!, tested by large mailers since 1999, was deployed nationally in 2004, giving business mailers a web-based process for mail entry, payment, tracking, and reporting. In 2005, the Facility Access and Shipment Tracking (FAST) system replaced DSAS, managing drop shipments at facilities nationwide and giving mailers the ability to schedule multi-stop and recurring appointments. In 2009, the Postal Service completed deployment of Performance Based Verification, an automated process that used mailers' past performance to determine the frequency, sample size and type of verification to be performed on large mailings. Meanwhile, the Electronic Verification System, introduced in 2007, allowed bulk parcel shippers to submit manifests and pay for postage electronically, eliminating the need for postal clerks to visit mailers' plants and distribution centers to verify shipments.  The manifests were randomly sampled for accuracy after the parcels enter the mail system. eInduction, launched in 2013, let large mailers deliver shipments of mail to processing facilities without having to fill out paper forms.

Sorting Flat Mail, 2000
Sorting Flat Mail, 2000
Sorting Flat Mail, 2000
Beginning in the 1990s, the Postal Service further automated its flat sorting operations to hold down operating costs. New automated flat sorting machines could process mail more than twice as quickly as the Flat Sorting Machine (FSM) 881 pictured above, which relied on operators to key in part of the address.

To help keep postage rates low, the Postal Service worked to further automate its processing operations. It upgraded flat sorting machines to increase the number of flats that could be automatically sorted to the correct delivery office, and in 2011 completed the deployment of flats sequencing system (FSS) machines, which could sort flats into delivery sequence. The Postal Service also further automated parcel processing, deploying new sorters and upgrading existing equipment to increase the machines' productivity. And in 2004, the Postal Service began deploying the postal automated redirection system (PARS) to its processing plants, to identify and redirect forwardable mail during processing. PARS also automated the processing of change-of-address forms and electronically notified mailers who subscribed to ACS.

Weighing Mail at a Bulk Mail Entry Unit, 2006
Weighing Mail at a Bulk Mail Entry Unit, 2006
Weighing Mail at a Bulk Mail Entry Unit, 2006
Bulk mailers qualified for discounted rates if they pre-barcoded and presorted mail while complying with envelope and address size and quality standards, which were developed in partnership with MTAC.

The Postal Service also increased its educational outreach to small- and medium-sized businesses. In the early 2000s, the Postal Service added the "Business Mail 101" application to usps.com to help beginning or infrequent mailers choose the best mailing solution for their businesses or organizations, and a Business Rate Calculator on Postal Explorer to automatically compute rates for every class and quantity of mail. In 2001, a "Shipping Solutions" website launched, and in 2004 customers were given the ability to design and download Business Reply Mail at usps.com/replymail. "Workshop-in-a-box" PowerPoint presentations at usps.com/nationalpcc, meanwhile, covered various topics, including the benefits of using direct mail. The Postal Service also developed a streamlined new series of Domestic Mail Manual (DMM) tailored to specific user groups — the DMM 100, A Customer's Guide to Mailing, for retail customers; and the DMM 200, A Guide to Mailing for Businesses and Organizations. It also offered seminars on advertising with mail, nationwide "Grow Your Business Day" workshops, Business Mail Academy courses, and a Mailpiece Design Professional certification program, among other offerings.

Pieces of Mail, 1930-2010 chart
Pieces of Mail, 1930–2010
Pieces of Mail, 1930–2010
After World War II, mail volume rose steadily until the 1970s, when worksharing discounts contributed to a surge of First-Class Mail and Standard Mail. Since 2006, total mail volume has receded.

The Partnership Continues

When we work together to enhance the value of the mail … the entire industry benefits.
United States Postal Service, 201526

Over the course of the twentieth century, the partnership between the Postal Service and the mailing industry grew and blossomed. From large-volume mailers cooperating with postmasters to expedite particular mailings, to all segments of the mailing industry advising the Postal Service on policies and programs as well as pilot-testing improvements — the partnership helped the Postal Service deliver for America.

In the 1960s, the Postal Service formed Postal Customer Councils (PCCs) in hundreds of cities as well as the Mailers' Technical Advisory Council. PCCs met regularly with local postal officials to exchange ideas and information and helped postal leadership launch its "mail early" plea to businesses. MTAC aided mailers' compliance with new requirements for sorting mail by ZIP Code. Both PCCs and MTAC have served as vital channels of communication for more than fifty years. Since its creation, MTAC has also provided technical advice and feedback vital to the formation and implementation of many other postal innovations, such as the ZIP+4, Move Update standards, postal certification programs, and the Intelligent Mail barcode. MTAC also suggested and helped fine-tune the worksharing discounts that have been offered to mailers since the 1970s. Worksharing helped keep postage rates low both directly — via discounts earned by mailers — and indirectly, by reducing postal labor needs, which helped curb rate increases. Low postage rates, in turn, boosted mail volume. Steadily growing volumes of First-Class Mail and Standard Mail surged after worksharing discounts were introduced, with total mail volume peaking at 213 billion pieces in 2006.

Picking Up Packages, 2014
Picking Up Packages, 2014
Picking Up Packages, 2014
Between 2010 and 2014, the number of packages in the mail increased by nearly 30 percent.

Since that time, total mail volume has ebbed. The decline of First-Class Mail reflected the diversion of transactional mail to electronic media. Yet, while the Internet significantly disrupted many traditional modes of hard copy advertising, such as newspapers and magazines, advertising mail continued to hold its market share. Much of the drop in Standard Mail was attributable to the Great Recession which gripped the nation beginning in 2007 — the ability of mail to connect businesses to their customers with highly targeted, relevant messages remained unmatched by digital media. Online retailers, meanwhile, helped drive steady growth in package volume, which increased by nearly 30 percent between 2010 and 2014.

For more than a century, the Postal Service and the mailing industry had cooperated to deliver larger and larger amounts of mail. The partnership became even more important as the Postal Service faced a new challenge — delivering less mail, to an ever-expanding delivery network, using only its own revenue, with its ability to cut operational costs constrained by Congress. Reflecting on the partnership between the Postal Service and the mailing industry upon MTAC's 50th anniversary in 2015, Postmaster General Megan Brennan noted that the partnership "has endured for fifty years because it enables the Postal Service and the mailing industry to work better together, and enables us to grow stronger together." The key to meeting new challenges, she stated, was to continue to work "collaboratively, strategically and with a shared commitment to invest in our future."27


1) Associated Advertising Clubs of America, Annual Convention of the Associated Advertising Clubs of America (Boston: Pilgrim Publicity Association, 1912), 47, hathitrust.org (accessed July 20, 2015). The phrase was an old one — as early as 1854, the British economist George Rickard stated "the luxuries of one generation become the necessaries of the next."

2) In the early 1800s, postmasters could mail newspapers (and letters) for free, while publishers could mail newspapers to each other for free. Postmasters apparently also frequently delivered newspapers to customers without collecting postage, resulting in unintentional free delivery. Because postmasters often did not or could not collect postage from newspaper recipients, Congress mandated prepayment of postage by publishers in 1875. Local newspapers, meanwhile, were delivered postage-free for most of the years between 1845 and 1963. Members of Congress, meanwhile, could send mail postage-free throughout most of the nineteenth century with few or no restrictions, except for during the years 1873 to 1895.

3) 5 Stat. 733; Act of March 3, 1845, effective July 1, 1845.

4) Simplified addressing was briefly extended to city addresses in 1934 and 1953, but soon ended under pressure from newspaper publishers. Every dollar that advertisers spent on direct mail was potentially a dollar not spent on newspaper advertising.     

5) U.S. Post Office Department News Release, July 24, 1922.

6) The 1900 Annual Report of the Postmaster General, on pages 244 to 249, includes a chart showing that in an October 1899 survey of first-class post offices, five cities accounted for 53 percent of all mail, by weight — New York, Chicago, Boston, Philadelphia, and Washington, D.C.

7) Presorting mail was the sixth of eleven "conditions upon which mailings of third and fourth class matter will be accepted," which were printed on the first edition of Post Office Department Form 3601, "Permit to Mail Third and Fourth Class Matter Without Postage Stamps Affixed, On the Prepayment of the Lawful Postage Rate in Money, as Provided by the Act of Congress Approved April 28, 1904" (copy in files of USPS Historian). Presorting was sometimes done under the supervision of postal clerks, and sometimes by postal clerks themselves, working in companies’ mailrooms. When a Chicago mail order firm mailed out a record-breaking 6,000,000 catalogs in 1909, 25 postal clerks worked “for some time” in its shipping room, sorting the catalogs into labeled sacks (Chicago Daily Tribune, March 16, 1909, 13).

8) The requirements for using precanceled stamps later changed. Postmasters in a few U.S. cities supplied precanceled postage stamps to customers as early as the 1870s, apparently on their own initiative.

9) The Union Postal Clerk, April 1914, 28; and May 1914, 55, hathitrust.org (accessed September 24, 2015).   

10) Harry J. Maginnis, President, Associated Third Class Mail Users, in a letter to Postmaster General Lawrence O'Brien dated November 19, 1965 (copy in files of USPS Historian).

11) U.S. Post Office Department release No. 80, Address by Frederick C. Belen, Assistant Postmaster General, Bureau of Operations, at Sixth Annual Circulation Seminar for Business Publications, Chicago, Illinois, June 7, 1961, 1–2.

12) U.S. Post Office Department release No. 92, July 19, 1961, 2.

13) U.S. Post Office Department release No. 80, Address by Frederick C. Belen, Assistant Postmaster General, Bureau of Operations, at Sixth Annual Circulation Seminar for Business Publications, Chicago, Illinois, June 7, 1961, 3–4.  

14) Charles Pace, "Reflections," circa 2004 (copy in files of USPS Historian).

15) U.S. Post Office Department release No. 92, July 19, 1961, 4.

16) U.S. Post Office Department, Memo to Mailers, October 1967, 9.

17) U.S. Post Office Department, Memo to Mailers, August 1966, 1.

18) U.S. Postal Service, Finding Common Ground: The Report of the Blue Ribbon Committee, 5. The committee, which consisted of top industry and postal officials, was appointed by Postmaster General Marvin Runyon in 1996 to advise the Postal Service on ways to improve its operations and services.

19) Second- and third-class mail had to be presorted by ZIP Code to be eligible for bulk postage rates since 1967; to qualify for the "5-digit presort" discount off the basic bulk rate, minimum quantities of mail had to be sorted to each ZIP Code.

20) Robert H. Cohen et al., Office of Rates, Analysis and Planning, U.S. Postal Rate Commission, "The Impact of Using Worksharing to Liberalize a Postal Market," 7–10, February 2001 (accessed July 8, 2015).

21) Ibid, 7.

22) U.S. Postal Service, Memo to Mailers, November/December 1985, 4.

23) U.S. Postal Service, Memo to Mailers, July 1983, 2.

24) Postmasters were authorized to receive advance deposits from publishers, to pay for more than a single mailing, by 1902.

25) U.S. Postal Service, Comprehensive Statement on Postal Operations, 2001, 36.

26) U.S. Postal Service, "MTAC Anniversary, 1965–2015: Celebrating 50 Years of Achievement," (accessed September 24, 2015), 1.

27) Ibid., 2.