We introduce collaborative tagging and faceted search on structured P2P systems. Since a trivial and brute force mapping of an entire folksonomy over a DHT-based system may reduce scalability, we propose an approximated graph maintenance approach. Evaluations on real data coming from Last.fm prove that such strategies reduce vocabulary noise (i.e., representation's overfitting phenomena) and hotspots issues.
@cite_12: 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.
PINTS comes as a building block of Tagster @cite_12 , a distributed content sharing and tagging system where the user-resource-tag graph is stored in a DHT. A dedicated storing index is used for each tagging relation, so each edge in the graph is stored at different overlay responsibility areas. For this reason, one lookup for each edge retrieval is needed, and this could make the navigation expensive in systems with a huge number of tags and objects. Furthermore, navigational aspects between related tags is not explicitly taken into account.