I don't do social media.
It seems that every week, there's a story about someone's Facebook?Twitter/Myspace/Whatever account getting someone in hot water, be it their employer who objects to a post, a prospective employer who doesn't like what they posted . . . or law enforcement, who sees the postings as confessions of some crime.
Although I may do something on "LinkedIn" soon . . . purely for professional reasons. (Resume, patents awarded, that kind of thing.)