Social networking – am I missing anything?

I’ve regarded MySpace, Facebook, and other social sites as irrelevant at best. I admit I’ve reached this opinion without visiting any of these sites, opening an account, or participating.

Am I missing anything or are these just the latest fad, soon to go the way of the CB radio, the ISP-generated personal web page, and the abandoned blog?

If you participate in these types of web sites, which ones do you prefer and why?