Social Networking Sites

I'm a fan of social networking, and hoping to stay that way - without becoming obsessed. I used to have a bebo account, but currently have a facebook account for friends etc, and a MySpace account to follow bands/music.
I like the remote contact aspect the social networking allows; you can keep in contact with people who live 5km or 5000km away. I also like the 'post & reply' (or not) operation, rather than being in a real-time chat room (although I have used the chat facility on facebook myself). It's a good way to keep up with people and stay as close/distant as you like, without the personal 'closed' aspect of email. It's good to be able to use other tools - such as linking a picture or video to your profile - and say more than could have been expressed in text. Social networking sites also a good way to gauge what's happening in the world via the online community - just imagine if 9/11 had happened in this age of intense social networking.
As much as I like social networking, I do think there is a danger of liking them a little too much. One of my friends on facebook posts 5+ links etc EVERY DAY. I prefer quality, not quantity...
I also dislike the vapidity that can pervade these sites - I don't really need to know what so-and-so had for breakfast.
And one more thing I don't like lately is that some of the functions seem to change every time I login. A lot of the operations of the photo albums/comments, and how much access external private enterprise have to your account seem to change fairly regularly.

On the other hand, it's all free, so as long as you understand the privacy risks you shouldn't complain!