Since I seem to be on Friendster and Orkut and junk for no reason these days I was reading about some other social networks and the most interesting one I saw was Songbuddy which tries to connect people based on links to music:
SongBuddy is a new way to find music that's already available on the Internet. By finding songs on bands' and labels' sites and sharing the address of those songs with your friends, you can explore music you'll love that you wouldn't hear anywhere else. So sign up, make some friends and list some music. You won't even need to install any software, SongBuddy works with your current media player.
The site runs incredibly slow for me for some reason so I can't check it out much or represent for myself and my music, but I very much dig the idea. I remember watching something on the Discovery channel a while back that claimed there's no evolutionary use for music except for helping build communities.