Yeah. And it's also a bit like trying to read signal out of noise. Someone into a certain genre may grow into a different one for all sorts of reasons. I've been increasingly thinking that a true recommender system would require some sort of consciousness. Plus a recommendation from a friend usually comes with some sort of explanation of why its good and can be useful to push past reasons to dismiss it. For example, I hate most cop shows but I love The Wire. It took someone trusted saying "it's more of a social commentary on the dynamics of a crumbling American city" for me to really give it a shot.