Recently I've friended a handful of adults on Facebook ("adults" meaning people who are around my parents' age.) It seems it's finally acceptable for normal adults to join without feeling completely geeky. Congrats, Facebook people.
I know there are Facebook haters out there and certainly don't condone people who spend their entire existence on the site. But I do have to say that Facebook has proven its worth, at least to me. I'm probably the most terrible person in the world at keeping in touch. Email tag never lasts very long with me and I try to avoid talking on my cell phone if I can get away with it. However, for some reason, ever since I joined Facebook (I think it was around 2004) I've been a lot better at keeping track of people and letting people keep track of me. I think it's because of the lack of commitment it requires. You can jot a five-word message on someone's wall without having to commit to an entire conversation, and whether that person replies back to you or you ever write on their wall again doesn't matter. Even without regularly communicating to anyone you can "keep in touch" with people because you can see their recent pictures and statuses. Some may argue that this marks the deterioration of meaningful human relationships. But really, the way I see it, it's better than nothing, which I think is the inevitable alternative.