Well, I looked at MySpace long ago and was turned off by it. I thought its design was too much like my freshman year locker to be of any interest - messy, stuff all over...
FaceBook is more attractive but you have to be careful not to get sucked into the many games and quizzes. I have a friend who started sending me stuff almost daily. Useless bits of quizzes. But I was able to find my old college roommate on there and reconnect. So that was awesome. (If a blast from the past.)
I get frustrated and perhaps a bit anxious with Facebook, however, in the fact that I do have personal information Out There. [Cue the Twilight Zone music.] So I try to keep things PG even though I am not a PG personality at all times. Sigh. I get tired of having aliases and pseudonyms.
I really would like do more work-related networking. Have a group of cyber buddies that you can talk shop with and bounce ideas off of without worrying about politics, dud ideas...just be able to throw it all out there.