You signed up for FaceBook or MySpace and eagerly started filling in your profile. Name, check. City, check. Birth date, check. (Gotta have your friends send you happy wishes on your birthday, right?) Job history, check. Spouse, check. Throw in some pictures of yourself and the kids for good measure.

Except there's a catch. Every little bit of information that you add to your profile could be one more piece of the identity theft puzzle. And some information is more telling than you can imagine. Did you add your birth date? That's something that may be better left unpublished, as it is one critical piece of information that banks and credit card companies use to identify you.

Have you hooked up with some family members? That might give a clue to your maiden name, another potential identifier. Even worse... those socializing on genealogy websites might be sharing information like your mother's maiden name, another key piece of information for financial services companies.

Don't take my word for it. Computer security experts say that information shared on social networking sites leaves people very vulnerable to identity theft. And often they don't realize how much information they've shared until it's too late. Tread carefully when sharing information on any website. Before your share your life's story, ask yourself what an identity thief would be able to do with that information.

Tracy L. Coenen, CPA, MBA, CFE performs fraud examinations and financial investigations for her company Sequence Inc. Forensic Accounting, and is the author of Essentials of Corporate Fraud.