The U.S. Postal Service lost $16 billion last year, despite having all sorts of advantages that most private businesses don't have. They have a near monopoly on first-class mail delivery. You want to deliver something to someone? You better not put it in their mailbox -- that's illegal. The U.S. Postal Service doesn't pay sales tax or property tax. They don't even pay parking tickets. With advantages like that, how do they lose money? They are part of the government, writes John Stossel, and that invites calcified, inefficient behavior.