I am one of those freaks that refuse to sign up for facebook. Not that there is anything wrong with it. In my personal circle it is because I don't approve of gossip. And my daughter doesn't like the idea of mama on facebook (even though she is savy and responsible and I know she isn't misusing it). I will miss you all if you go away, thanks for being there for me these last several weeks. I don't have other moms with young kids, so I always enjoy the company.
I am also a "freak" not on facebook, but it's because I have a problem with FB. I don't want to openly dis, or anything, but FB (IMO) has an unethical UA, and especially for picture people, know that the UA states all photos and uploaded materials belong to FB, not you. Even if you delete it - they still own the cache. I don't know how long they maintain their data, but there's certainly an ethical bag of worms there. The official "press release" of FB is that privacy settings mean they wouldn't, um, sell your kid's picture to advertisers. But FYI, that is not what the terms of service say.
Summation: it's too sketchy, IMO.
I'm kinda hesitant to post this, for the risk of offending someone who loves FB, but I guess I feel an ethical obligation to remind people. I explain this to my students all the time (and about geotagging too). Of course, you are all much more social networking savvy than them, but... yeah, anyway, my intent is not to offend or derail. And I hope you all keep coming here too...