I don't know about the Spotify analysis here, but certainly cosign RateYourMusic, which I just learned about this last weekend and am now a little bit obsessed with. It's like IMDB crossed with Pinboard, and the list of new stuff I have to listen to now is long and intricately connected to what I already listen to. It's a pretty amazing resource, even if everyone there is wrong about Uncle Tupelo's "Anodyne".
I pay for it because it's dirt cheap and you get track ratings. If I discover an artist I use RYM to get the best 3 songs of their best 3 albums on YouTube. if I still like the band after that I'll buy the highest rated album.
I used it for like 5 minutes before paying for it, it's obviously great, and the "pro" upgrade has the funniest best feature ever (exclude ratings by the age of the rater).
