Great resource for new music and people with similar musical tastes.
Ever since I joined Last.fm last year, my musical environment has exploded. I'm continually finding out about new music, oftentimes to the point where I'm harassing the local record shop about "a Czech band that sings in French" or some other golden find from this website. I've been a subscriber for about a year now, and never looked back. This website has been an excellent way on keeping tabs of what artists are coming to my area, what sort of music my friends are into, recommending music to friends and the groups I belong to, finding out about new artists by listening to what's similar to artists I already like... seriously, Last.fm is ingenious. And well-designed, I might add.
this is THE REVOLUTION!