Helpful articles

I've found a few articles with more detail how exactly some sites take users tastes and make recommendations based on them. First there's What is the Music Genome Project, which details Pandora's time-consuming database work that took years before they could launch, then The New York Times had an article discussing both Pandora and Last.fm. more from the perspective of what users get out of the sites, and finally an interview with Last.fm co-founder Martin Stiksel.