@techreport{ilprints775,
          number = {2006-10},
           month = {April},
          author = {Paul Heymann and Hector Garcia-Molina},
           title = {Collaborative Creation of Communal Hierarchical Taxonomies in Social Tagging Systems},
            type = {Technical Report},
       publisher = {Stanford},
     institution = {Stanford InfoLab},
            year = {2006},
        keywords = {Tagging, taxonomy, hierarchy, annotation, metadata management, CSCW.},
             url = {http://ilpubs.stanford.edu:8090/775/},
        abstract = {Collaborative tagging systems---systems where many casual users annotate objects with free-form strings (tags) of their choosing---have recently emerged as a powerful way to label and organize large collections of data.  During our recent investigation into these types of systems, we discovered a simple but remarkably effective algorithm for converting a large corpus of tags annotating objects in a tagging system into a navigable hierarchical taxonomy of tags.  We first discuss the algorithm and then present a preliminary model to explain why it is so effective in these types of systems.}
}