In this paper we introduce a novel kind scenario where users use Rich Personal Semantic Web Clients to cooperatively create knowledge within “Semantic Web Communities”. Such communities are formed around P2P channels which work by exchanging patches of RDF information among clients. Once sufficient information has been collected locally at each client, rich and fast browsing of such "Semantic Web" becomes possible without generating external traffic or computational load. A prototype of such client, DBin, is presented and issues such as user interfaces and social aggregation model are discussed. We will focus in particular on the "Brainlet" paradigm, which enables community leaders to create and deliver domain specific user interfaces. The Brainlet creation process does not require programming skills, so that Semantic Web communities can be started up by domain experts rather than programmers.