Long before the days of speedy, overnight mail deliveries, postal service workers meticulously sorted through letters by hand and transported mail on horseback. “Most people treat the Postal Service like a black box,” USPS spokesperson Jim McKean tells The Verge. “That changed dramatically in 1963, [with] probably the biggest innovation the Postal Service has ever rolled out, called the ZIP code,” Kochersperger says. “The Postal Service is a driver of technological change,” McKean says. “It’s hard to overstate the amount of technology that the Postal Service has been involved in either popularizing or innovating over the last 250 years.”