Now I'm not Saying it's 100%
But it's not a total waste of time in terms of finding new music, either. Discover Music - Pandora.
Basically, you punch in the name of a beloved band, and Pandora uses black magic and voodoo to come up with other bands that you may or may not like. And if you don't like a recommendation, just skip on to the next one or simply let songs stream. I'm betting this turns into a pay service shortly, so you might want to check it out while it's still free.
EDIT to post that indeed it's a pay service. Not sure how much, but what's intriguing for free may not be worth a nickel. Not if you're a cheapskate like me...