As someone who builds recommender systems for a living, let me assure you that the output of the netflix prize was perhaps 10% of what you need to actually build a good recommendations product.

Don't forget that Hunch's system is real-time (this is very hard), and is more than just scalable collaborative filtering for items of the same kind. They can ingest a Twitter or Facebook profile, infer your "taste profile", and start recommending things instantly; "things" meaning books, films, music, events, places etc etc.

See my above reply to suking--$80m is kind of a bargain.