So, I know I'm probably about five years behind on this, but... I don't ever really bother looking into music sites much until they've caught on. I'm a late-bloomer with most internet things (that way, it hurts me less if/when they fail, like Guzzlefish did).
But anyway, I just randomly decided to go to Last.fm and punch in "Dream Theater," who are probably my favorite band overall. It... started playing... Iced Earth for me. Iced. Earth.
It's like it knows me and wants to be my friend.
I might have to keep exploring this. I'm just sorry I didn't look into it sooner when my girlfriend showed it to me.