Peer-to-Peer Information Search: Semantic, Social, or Spiritual?

We consider the network structure and query processing capa bilities of social communities like book- marks and photo sharing communities such as del.icio.us or fl ickr. A common feature of all these net- works is that the content is generated by the users and that us ers create social links with other users. The evolving network naturally resembles a peer-to-peer sy stem, where the peers correspond to users. We consider the problem of query routing in such a peer-to-pe er setting where peers are collaborating to form a distributed search engine. We have identified threequery routing paradigms: semantic routing based on query-to-content similarities, social routing ba sed on friendship links within the community, and spiritual routing based on user-to-user similarities s uch as shared interests or similar behavior. We discuss how these techniques can be integrated into an exist ing peer-to-peer search engine and present a performance study on search-result quality using real-wo rld data obtained from the social bookmark community del.icio.us.