Ask HN: Why is Facebook still wildly popular but MySpace, not
Friendster, MySpace and others have come and gone but Facebook is still here and extremely popular. Why?
The short of it is that during a crucial point in time Facebook positioned itself as a high-class alternative to MySpace. But the article puts it better than I do.
Somewhere towards the end of this cycle, we’ll probably want something a little classier again (a new classy, not the old classy).