Why is MyFace so Popular?

Link to a blog about why MySpace is so popular in spite of it's horrible UI. I have been wondering a similar thing about Xanga recently. I don't get why so many people us Xanga when it's interface is so horrible. Even some of my programmer friends use it. Of all people they should know better. Anyways, the conversation that is in the comments section discusses a lot of interesting ideas. I don't really know if I really agree with it all, but something to think about.