For anyone who's trying this, I recommend basing your effort on factor models (i.e., the thing that won the netflix prize). It works very well for us at Zite.

For anyone who's trying this, I recommend basing your effort on factor models (i.e., the thing that won the netflix prize). It works very well for us at Zite. (Content models are the other, probably less interesting, 50% of the solution.)