The United States Postal Service is, well, the postal service in the United States. (Duh!) Although known by many Internet users as snail mail, it is one of the world's most efficient mail-moving operations, moving billions of letters each year at 32 cents each. Services include First Class Mail, where your mail takes a long time to arrive, Priority Mail, where the mail goes through in 2 days, and Express Mail, an overnight delivery service created to compete with the likes of FedEx.