The 2nd International Workshop on Information Heterogeneity and Fusion in Recommender Systems (HetRec 2011, http://ir.ii.uam.es/hetrec2011) has released datasets from Delicious, Last.fm Web 2.0, MovieLens, IMDb, and Rotten Tomatoes. These datasets contain social networking, tagging, and resource consuming (Web page bookmarking and music artist listening) information from sets of around 2,000 users.

The datasets were generated by the Information Retrieval Group at Universidad Autónoma de Madrid (http://ir.ii.uam.es). Before using these datasets, please review the README files for the usage license and other details.