I've heard myspace users have a tendency to be a bit 'emo'. I use facebook myself - damned useful for remembering peoples' names. Also quite good for getting in touch with old school friends. For instance, randomly browsing some peoples' profiles, I found someone I'd been to school with several years ago was visiting my home city...

You wouldn't believe how popular facebook is amongst university students - I've started counting the time before it's mentioned in conversation amongst a group, usually not long...