There is also another type of postal code, the ZIP + 4 code. According to unitedstateszipcodes.org, the ZIP + 4 was established in 1983 and identifies an even more specific location within a ZIP code.

Everyone has memorized exactly two ZIP codes: 90210 and whatever their own ZIP code is. Why do we use zip codes? The entire practice of using ZIP codes is a relatively new system that was put in ...