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 ...

That used to be the ZIP code for Silver Cliff, Colorado, before the U.S. Postal Service removed it from use and forced the town to use neighboring Westcliffe’s ZIP code. “We lost our identity,” said ...

For some credit card purchases in Canada, a postal code is required as a security measure. If using a credit card in the U.S., you may need to use a ZIP code instead. Many or all of the products on ...