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_0: Concept hierarchies greatly help in the organization and reuse of information and are widely used in a variety of applications, such as data warehouses. In this paper, we describe a method for efficiently storing and querying data organized into concept hierarchies and dispersed over a DHT. In our method, peers individually decide on the level of indexing according to the incoming queries. Roll-up and drill-down operations are performed on a per-node basis in order to minimize the number of floods for answering queries on varying levels of granularity. Initial experimental results support this argument on a variety of workloads.
In @cite_0 an efficient indexing scheme for storing and retrieving concept hierarchies over a fully decentralized system is given, even if folksonomies are not taken into account.