The problem with collaborative filtering is that there's a lot of magic going on that the user does not understand. Some users like to have more control over personalized recommendations and social networks can give them that control.
That website has some great case studies available on recommender systems available for finding "music", "content", etc. I would much rather prefer that a computer do my work than myself. Web users have a terrible attention span so such a system would work to their benefit by eliminating the need to click-and-find content. For anyone interested, I expressed my ideas on collaborative filtering here: http://www.socialdegree.com/2007/01/15/interview-w-shuzakcom-founder-jawad-shuaib/
