OKBook: Peer-to-Peer Community Formation Xi Bai 1 , Wamberto Vasconcelos 2 , and Dave Robertson 1 1 School of Informatics, University of Edinburgh, UK 2 Department of Computer Science, University of Aberdeen, UK xi.bai@ed.ac.uk, w.w.vasconcelos@abdn.ac.uk, dr@inf.ed.ac.uk Abstract. Many systems exist for community formation in extensions of traditional Web environments but little work has been done for form- ing and maintaining communities in the more dynamic environments emerging from ad hoc and peer-to-peer networks. This paper proposes an approach for forming and evolving peer communities based on the sharing of choreography specifications (Interaction Models (IMs)). Two mechanisms for discovering IMs and collaborative peers are presented based on a meta-search engine and a dynamic peer grouping algorithm respectively. OKBook, a system allowing peers to publish, discover and subscribe or unsubscribe to IMs, has been implemented in accordance with our approach. For the meta-search engine, a strategy for integrat- ing and re-ranking search results obtained from Semantic Web search engines is also described. This allows peers to discover IMs from their group members, thus reducing the burden on the meta-search engine. Our approach complies with principles of Linked Data and is capable of both contributing to and benefiting from the Web of data. 1 Introduction Nowadays, providers care more about how communities (e.g. via eBay) rank their products and services than how search engine giants rank them. On the other hand, service requesters trust recommendations by other peers in social commu- nities more than advertisements from service providers. Therefore, the commu- nity plays a more and more important role in addressing service discovery issues. Several systems exist for community formation in extensions of traditional Web environments but little is known about how communities might be formed and maintained in the more dynamic environments emerging from ad hoc and peer- to-peer networks. A difficulty in establishing communities in traditional peer-to- peer systems is that there is no structure that can be used as a basis for forming communities; there is nothing analogous to the relations used behind the scenes in Web-based social networking stems in order to infer community information (such as friend-of-a-friend relationships). Some recent peer-to-peer knowledge sharing systems have, however, used languages for specifying choreography between peers that can be used to provide the relations to build social networks. The Open- Knowledge 1 project has developed a peer-to-peer knowledge sharing system in 1 http://www.openk.org/ L. Aroyo et al. (Eds.): ESWC 2010, Part II, LNCS 6089, pp. 106–120, 2010. c  Springer-Verlag Berlin Heidelberg 2010