@codinghorror @munin I assume you mean zip code?

All of us throughout the world learned in the 1980s and 1990s about "90210". We use it all the time when a web site asks for any sort of verification that we're in the U.S.

Ironically, that zip code might be a tell for our age! It means we were teenagers in the late 80s and 90s. Some zip codes indicate wealth, but that one could reasonably be used to identify Gen-X.