Reconstructors, Novelty and the Algorithm vs John Peel
Pandora vs Last.fm - read the MeFi thread for emerging value drivers. In short, there's a big problem with collab filter based solutions - novelty.
EG, Amazon keeps telling you to buy the same bloody books, over and over again (as I'm sure you're painfully aware of). Collaborative filters get stuck on local optima, if I'm allowed to talk fitness landscapes for a sec.
Let's go back to my example of the DJ for a sec. As this MeFi commenter says:
"...What I also need is John Peel back. I need someone to say "listen to this apparently random track, you may hate it now, but it's good for you in the long run and it made me honk like an excited goose".
DJ's are like collaborative filters - but the best ones are also sources of novelty. Noise, if you like, - but
good noise. Filters that can jump from peak to peak - from things I might like
now, to things I will like when my preferences will evolve (or, better yet, that evolve my preferences). Algorithmic solutions don't do this yet - and probably won't for a while, because it's a (really) hard problem. But it's also a (really) big market gap.
I hope that made sense :)