Tagging with DHARMA, a DHT-based Approach for Resource Mapping through   Approximation
  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. 
Luca Maria Aiello, Marco Milanesio, Giancarlo Ruffo and Rossano   Schifanella
cs.DC cs.SI