By the Associated Press

— Provide enough information for your friends to be able to identify you — but not so much that someone could use information to steal your identity. There's no reason to include your entire resume, from education to work history.
— Consider making your profile private so people you don't know can't "scrape" information and images from it.
— Even if your profile is private, remember that your information and photos also can be accessed by third parties through your friends — and through applications developers on such sites as Facebook and MySpace.
— Remove social-networking applications you're not using and check out the creators of those you do install. If something seems suspicious, report it.
— Don't use the same password for social network sites that you do for online accounts that have banking and credit card information.
— Check for updates on privacy policies on various sites you use.
— Never assume that anything you post online is completely private. Trust your instincts. And remember that, ultimately, responsibility for the information, photos and video you post is yours.

Source: Pew Internet & American Life Project; Adrienne Felt, University of Virginia; Kroll Inc.