Comparison of social classification systems in a heterogeneous environment

Abstract

This paper presents the results of practical studies comparing five well established social classification services for tagging of bookmarks (del.icio.us, BibSonomy bookmarks) and publications (BibSonomy publications, CiteULike, Connotea) in the context of service interoperability and integration. Contrary to most of current research we exclusively focus on the usage of RSS feeds for retrieval of tag-related data. Here we exploit "recent" feeds, as this method of data retrieval corresponds directly to the way users can retrieve data from these services, e.g. for tag suggestions. We motivate the preferred usage of feeds compared to full site grabbing, and present analysis results of feed data from the same period of one month concerning feature distribution, growth, stability and convergence aspects. Furthermore we compare tag spaces and their intersections for potential interoperability and integration of these services, and reveal that tags in practice are not really as freely chosen as often promised. © 2009 Springer Berlin Heidelberg.