social media is a good source of info for things that they can't legally ask you during an interview or that you may lie about, they want to profile you as thoroughly as possible so maintaining your privacy makes you a less desireable candidate for employment
So wrong it's not even funny. I've hired / interviewed many candidates for jobs and generally speaking, the less I know (to an extent) the better. It's easy to judge character, work ethic, intentions, skills, and overall chemistry with an individual based on interviews and talking with them face to face. I do find any reason to not hire someone, and if I have a lot more information that doesn't pertain to the job but it can be based of my own personal preference (ie, facebook information that is publicly shown), then I can nitpick all I want.
No facebook? I won't ask for it anyway, I pre-screen that, along with linkedin, youtube, myspace, etc. (I had one guy who was a club promoter and one of his references was a convicted pedo, hurray facebook)
Companies that force you to see your information are NOT companies you want to work for. A lesser degree that I've seen is that the employer adds the potential employee as a friend and will be upfront about it. Or if you want to be sneaky, use a doppleganger account.
If you are smart enough to clean up your photos on facebook, or deactivate it so I don't find any reason to think you aren't a qualified applicant during prescreening, then you are doing it right.
It's like an unwritten part of the interview process, "cover letter, resume, dress shoes, shirt and tie, and a squeaky clean or deactivated facebook page".
You can be double cunning by making your own "fake" facebook account with about 20 fake friends and don't post anything in it except some updates once a month. And with your real account make it very private to where you won't show up in the search.