You sure those sites do collaborative filtering? AFAIK, the 'front page' is the same for all, and real CF would show you a personalised page depending on your t

You sure those sites do collaborative filtering? AFAIK, the 'front page' is the same for all, and real CF would show you a personalised page depending on your tastes. Like movielens does for movies. http://en.wikipedia.org/wiki/Collaborative_filtering http://en.wikipedia.org/wiki/Collaborative_filtering