Unified Matrix Factorization Model for recommendation
Collaborative filtering (matrix factorization) suffers from cold start problem. On the other hand, feature based approach can hanle cold start problem, but its recommendation has limited coverage.
Unified matrix factorization is a technique can handle both situtations. Its incorporate side information into the model.
Reference: http://cseweb.ucsd.edu/~elkan/ECML2011LinkPrediction.pdf