Credit card fraud is identity theft in its most simple and common form. It can be accomplished either through a scenario like the one we just mentioned, or it can happen when your pre-approved credit card offers fall into the wrong hands. All a person has to do is get these out of your mailbox (or trash can) and mail them in with a change of address request and start spending. Someone can even apply for a credit card in your name if they have the right information. You won't know a thing about it until the credit card company tracks you down and demands payment for the purchases "you" have a racked up.

http://money.howstuffworks.com/identity-theft1.htm