shakh your bootie

Linked in is good - I use that, too. FB seems to be popular for professional networking in certain industries - e.g. digerati-types & media luvvies. I have had people from leading edge tech firms contact me through f/book becuase of some of the prof interest groups i'm listed under.

Increasingly, HR people will check you on fb as part of the selection process - that is why I'd recommend keeping it fit for public consumption.