This might be because we ship around 30k packages a month here at Adafruit, but shipping stats and stories totally fascinate me. Learn about the history of United States postal codes from Dion Lee and Mac Schneider at Vox.
Zip codes were invented in 1963 to help the United States Postal Service deal with huge increases in mail volume. The Zone Improvement Plan, or “ZIP” code system of addressing, organized mail delivery by dividing the country into 10 regions and assigning five digits increasing in specificity: from region to large sorting centers to smaller post offices. To promote the new system, the USPS released publicity materials featuring Mr. Zip, a cartoon character, and a song about zip codes from a band called The Swingin’ Six.