Collaborative modeling for recommendation. Implements variational inference for a collaborative topic models. These models recommend items to users based on item content and other users' ratings. Written by Chong Wang. Fun fact: this inspired the New York Times' engine (blog post)!
http://www.cs.cmu.edu/~chongw/data/citeulike/
http://www.cs.cmu.edu/~chongw/data/citeulike/
Chong Wang and David M. Blei. Collaborative topic modeling for recommending scientific articles. In KDD 2011. PDF