Tag Sources for Recommendation in Collaborative Tagging Systems.

Collaborative tagging systems are social data repositories, in which users manage resources using descriptive keywords (tags). An important element of collaborative tagging systems is the tag recommender, which proposes a set of tags to each newly posted resource. In this paper we discuss the potential role of three tag sources: resource content as well as resource and user profiles in the tag recommendation system. Our system compiles a set of resource specific tags, which includes tags related to the title and tags previously used to describe the same resource (resource profile). These tags are checked against user profile tags - a rich, but imprecise source of information about user interests. The result is a set of tags related both to the resource and user. Depending on the character of processed posts this set can be an extension of the common tag recommendation sources, namely resource title and resource profile. The system was submitted to ECML PKDD Discovery Challenge 2009 for "content-based" and "graph-based" recommendation tasks, in which it took the first and third place respectively.