Identity thieves steal personal data. They may use low-tech strategies such as dumpster diving (going through your trash to find bank statements and pre-approved credit card applications), stealing your mail, shoulder surfing (watching you punch your telephone or credit card number into a phone or enter your secret password into an ATM machine), listening to your account number when you make hotel or car-rental reservations or buying your information from unscrupulous store clerks.

Others employ high-tech methods such as capturing credit card or account numbers when you enter them on an unsecured Internet site, "phishing" (sending out a fraudulent e-mail that tricks you into disclosing personal information), stealing laptops with corporate or government data or hacking into Web sites. Some dishonest employees use small devices called skimmers to swipe your card and later download onto a personal computer.

Once they have your data, thieves might open bank or credit card accounts in your name to make fraudulent purchases or pass counterfeit checks. Thieves might change your address without your knowledge so you won’t even know you’re being billed until the problem has become huge.

For details on how thieves operate, go to http://www.ftc.gov/bcp/edu/microsites/idtheft/consumers/about-identity-theft.html