''Social''...

Because it helps you connect with friends from different places. Its very convenient to use and offcourse some people simply like to tell what they are doing every minute of the day. I think they are good if used properly. Sharing photos and videos etc is particularly good as people from far away can see them.

I first heard of facebook from a friend who told me i should sign up on that website and add him as a friend, even though we are already friends in real life, he is a weirdo i guess. But in all honesty, most people join these sites to meet new people around the world, and to interact with them, who knows, they may have gotten bored of the friends/people in their community and don't have the means to travel, so why not jump on the interwebs and find a website like facebook/myspace and start getting loads of new friends? :D