Method for Enhancing Search and Browsing in Collaborative Tagging Systems Through Learned Tag Hierachies

A number of Web 2.0 sites support collaborative tagging systems, which allow users to tag resources with keywords. The tags enable search and retrieval of resources both for the user and for other users, using interfaces like a conventional search form or a tag cloud. A tag hierarchy-based search and retrieval system is provided that enhances the existing interfaces by improving search recall and allowing the discovery of even poorly annotated resources. The system uses tag co-occurrence information to automatically learn tag hierarchies. The learned hierarchies are used for automatically inferring additional tags to resources. These inferences are used to improve the recall of queries issued from a search form or via a tag cloud. The learned hierarchies can be viewed as an emergent ontology that is built up through the collaborative wisdom of a large number of users.