Another piece of useless fact, just in time for the weekend... Do you know what “ZIP” stands for? No? Thank me then:

In case you ever wondered, ZIP stands for Zoning Improvement Plan. A relatively recent innovation, the codes only came about in the 1960s when the U.S. Postal Service decided it needed to figure out a better way to manage an increase in population, as well as an influx of business mail.

Before that, the postal service only used addresses, although large cities have had postal zones since 1943. Now, there are more than 40,000 ZIP codes. The first of the five numbers refers to a broad region, from zero for the Northeast (draw what conclusions you will) to nine for the West Coast. The second and third digits narrow to population centers and the last two represent individual post offices or postal zones.

-- Quoted from Yahoo!