In partial response to the observation by Decius that "The end of the reign of mass media means the end of the reign of mass culture", I offer this:

There is a danger that recommender systems may simply magnify the popularity of whatever is currently hot - that they may just amplify the voice of marketing machines rather than reveal previously-hidden gems. Even worse, their presence may drive out other sources of cultural diversity (small bookstores, independent music labels, libraries) concentrating the rewards of cultural production in fewer hands than ever and leading us to a more homogeneous, winner-take-all culture.

I'm no futurist, but I see little evidence from the first 300 days of the Netflix Prize that recommender systems are the magic ingredient that will reveal the wisdom of crowds.

You may recall that I recently wrote:

Obscure people, bring us your good arguments!

Tyler Cohen, "cult hero" and author of the recently published "Discover Your Inner Economist", notes that "recommender systems work best when combined with non-articulable knowledge." (Does MemeStreams some of have that?) Incidentally, for those of you in the DC area, Cohen will be at the 18th St. Lounge tomorrow for a Reason happy hour:

... come out and meet everyone. They also (seriously) have lots of beautiful women at these events, not like when I was a young libertarian.