I think what Surly's getting at is that there was a thread a while back about Pandora, La La and Last.fm, like in 2005 and there have been a few more since. Without a search function, good luck finding it.
I found pandora interesting for about a week. Then I stopped using it because I found the links a little detached. I was getting better results here and from Last.fm/Emusic recommendations.