Abstract. Collaborative tagging systems like Flickr and del.icio.us provide centralized content annotation and sharing which is simple to use and attracts many people. A combination of tagging with peer-to-peer systems overcomes typical limitations of centralized systems, however, decentralization also hampers the efficient computation of global statistics facilitating user navigation. We present Tagster, a peer-to-peer based tagging system that provides a solution to this challenge. We describe a typical scenario that demonstrates the advantages of distributed content sharing with Tagster.