Mr. Zip, a gangly cartoonish figure with wide friendly eyes and a neat blue mail carrier's uniform, emerged fifty years ago to help the U.S. Postal Service promote its newest idea: five numbers added to our addresses to more clearly designate our locations. In 1963, the post office was overwhelmed with billions of pieces of mail each year, and suburban sprawl was spreading Americans farther and farther away from each other. At most post offices, people still sorted mail by hand, putting letters one by one into pigeonholes. The best employees could sort faster than one piece of mail per second, but it wasn't enough. What was needed was machine sorting. And machines read numbers, not handwritten addresses.
"Put ZIP in your mail!" exclaimed a cheery promotional poster. Another ad, featuring a certain yellow-hatted detective, read: "Dick Tracy says: 'Protect your mail! Use ZIP codes!'" But the number that began as a sorting utility has since expanded far beyond our addresses. Today, our ZIP code determines how we are read by policy-makers, politicians, statisticians, pollsters, insurers, businesses, organizers, and marketers. Governments use ZIP codes to determine who gets what—and this, in turn, stokes our political divisions. Private companies use ZIP code information to determine if they will, or will not, move into our communities. Retailers collect ZIP codes from customers, which can protect against fraud, but also helps a consumer database marketer collect personal information on us without our permission.
ZIP codes, in other words, have evolved from finding where we are to defining who we are—far beyond our mailbox. "Organizations—business, government—can look at the mass of people we've become and break us down into usable points," says Nancy Pope, curator at the Smithsonian's National Postal Museum. "While it was designed to help our letters travel faster, it's become like an ID system we all agree to and all use."
As ubiquitous as they are now, the public originally balked at Zone Improvement Plan (ZIP) codes, even though they were (and still are) voluntary. ZIP codes came on the heels of telephone area codes, and Social Security numbers. People were wary of having another number to learn and use. Humorist Art Buchwald, writing a month after ZIP codes debuted, penned a syndicated column complaining about "the numbers racket":
The purpose of all these numbers, it is carefully explained to the American people, is to help speed up the American way of life. The truth of the matter is that while you do the work for the companies by playing their numbers game, they can lay off thousands of workers and use computers instead.
ZIP codes seemed to forbode a future where individual identity mattered less and less. Unlike area codes or Social Security numbers, ZIP codes narrowly locked in your location for use by what was then a department of the president's cabinet. It made some uneasy. It's why the likes of Ethel Merman were called on to help with the enormous promotional campaign: She performed in a public service announcement singing about ZIP codes to the tune of "Zip-a-Dee-Doo-Dah." The song was even released as a 45.
The fears of a dystopian future were overblown, but weren't exactly unfounded either. Nowadays, ZIP codes allow us to map the density of New York City cafes and even the dating scene. How did we get here?
In the 1960s, shortly after the codes debuted, commercial mailers jumped on them to precisely target their hometown markets. Third-class mail inundated the Chicago post office when businesses sent advertisements in unprecedented numbers, using ZIP codes for the first time to reach local customers. Most ads needed to be delivered swiftly because of time-sensitive sales and coupons. But, still relying on old machines, the Chicago Main Post Office—then the world's largest postal facility—couldn't manage the surge and shut down for three weeks in 1966. The ensuing investigation led to the Postal Reorganization Act of 1970, which removed the Postal Department from the cabinet and eliminated the Postmaster General position from the list of presidential appointees.
The same year, the Census started using ZIP codes as a data-sorting convenience. This ZIP code filter "has always been a large area of requests for data users," said the U.S. Census Bureau's Vincent Osier. Those users aren't just businesses targeting mailers, but also healthcare researchers looking to better understand systemic disparities and environmental differences.
"There's always a push from the data user community to get smaller and smaller so they can manipulate it for their own purposes," Osier said. But data disclosure concerns hold that back—any smaller would cut too close to individual people. "ZIP codes are large enough not to infringe on (privacy)," he explains.
Today, you can search Census data for ZIP business patterns, which, to the delight of market-measuring analysts, detail economic data in every corner of the country. As a result, ZIP codes shape how many sectors do business. In the modern-day insurance industry, it is illegal to redline by race and ethnicity—that is, to charge higher premiums to certain groups—but it is perfectly permissible to redline by ZIP code. (California is the one exception.) And wouldn't you know it? Price-gouging rates tend to target ZIP codes with a disproportionate number of racial and ethnic minorities.
Meanwhile, ZIP codes carry the cache of exclusivity for rich communities. Business journals in Portland, South Florida, Phoenix, and North Carolina are among those that rank the wealthiest ZIP codes, spotlighting residential areas with the highest average net worth. In pop culture, ZIP codes serve as an instantly recognizable cultural shorthand. There is "Beverly Hills, 90210," of course, as well as the reality show "Brooklyn 11223." Melissa and Joe Gorga on "The Real Housewives of New Jersey" recently declared their intention to "move to a better ZIP code." The fictional California city in the "Veronica Mars" television series was home to rich people described as "09ers"—that is, from the 90909 ZIP code.
There's actually no 90909 ZIP code, but the divisiveness they fuel is very real. Five Brooklyn politicians sued because Hurricane Sandy food stamps were only allotted to twelve ZIP codes. As affirmative action again moves toward the Supreme Court, citizens are going to war with schools experimenting with admission preferences for those living in particular ZIP codes. Staples, the office retailer, was among those exposed for offering better deals to customers in affluent ZIP codes. Residents of Hyde Park, Massachusetts won their battle this year to have USPS change their ZIP code: They were weary of the high insurance rates and low property values they faced because they shared a ZIP code with neighboring Mattapan, where poverty and crime are rife. "It has also associated (Hyde Park residents) with a neighborhood that some politely say has just never been their home," as the Boston Globe described it.
There's something disturbing about ZIP code uses that serve to divide us, rather than to connect us, as they were originally intended. Defining ourselves by ZIP code rather than metropolitan region, county, or even city diminishes the sense of the commonwealth. Perhaps it's not surprising, then, that the separation made manifest in mid-century sprawl and white flight were part of what gave birth to ZIP codes in the first place.
"Do We Really Want to Live Without the Post Office?" Esquire recently asked. It describes how USPS' massive financial trouble is rooted in bizarre Congressional mandates that demand urgent attention—not out of nostalgia, but because the postal service "is a miracle of high technology and human touch. It's what binds us together as a country." Whatever happens with USPS, the ZIP code has grown beyond the walls of the Post Office. There's no containing it now. ZIP codes no longer depend on their creator. But that doesn’t mean we shouldn’t push back when ZIP codes are used to exploit, manipulate, and divide us, or get uncomfortably close to crossing our standards of privacy. Maybe a new Mr. ZIP campaign is in order: "Protect your mail—and your community! Use ZIP codes—but wisely!"
Anna Clark is a writer living in Detroit. Her journalism has appeared in The American Prospect, The Columbia Journalism Review, Grantland, and other publications. She edits the literary blog Isak. Follow her at @annaleighclark.
Correction: The article originally misspelled the name of Art Buchwald. It has been corrected.