On July 1, 1963, the U.S. Post Office Department introduced the ZIP code program to get a handle on the heaping surplus of mail. Today, those five digits represent much more for American society. Back ...

The humble ZIP Code shows up in all kinds of surprising places. Planet Money looks at how it was born, how it transformed the mail and talks to one researcher who argues that it's gone too far. The ...

Back in the 1960s, there was a heaping surplus of mail in the U.S. Post offices were struggling to keep up with deliveries. According to the Smithsonian's National Postal Museum, mail volume reached ...