I don't have a FB account or any others for that matter. I use LinkedIn for my professional life but apart from that SMA is the only form of social networking that I partake in. Each to their own, my wife loves FB as it's a great way to keep up with her friends overseas.
One of my best mates made the following observation " I have about 200 Facebook friends but my 4-5 closest friends aren't even on face book"