Here's a MUST READ article over at Lifehacker concerning online profiles. It is rich with information and related links / resources. If you don't know this information, it IS hurting your online identity.
Dear Lifehacker,
I've been applying for a lot of jobs recently, and I'm wondering what kind of research an employer might do on me. What do they find in background checks? Do they look online too?
Sincerely,
Worried Searchers
Dear WS,
Employers often do quite a bit of research on you before they hire you. Background checks are common in some industries, and a general search online is almost guaranteed for every job these days. Here's what you can expect employers to look for, and how you can clean up what they'll find.
Read the full article via What Kind of Stuff Do Employers Search for When I Apply for a Job?.