The Web 2.0 has shown the importance of collaborative systems. It has allowed to transform a community of strangers into a community of collaborators. Nowadays, many social tools such as wikis and blogs are used by large communities; they produce a large amount of information. The Semantic Web aims structuring this information in order to make it processable by machines. Many social tools evolve by integrating the Semantic Web technologies. Wikis as social tools follow this trend and evolve towards semantic wikis. The introduction of Semantic Web technologies in social tools raises a number of problems such as scalability and support for collaborative editing processes which is necessary to maintain the quality of the content. In this thesis, we address these problems through an instantiation of the optimistic replication model in the context of semantic wikis, an instantiation replicating a new data type composed of wiki pages and semantic annotations. Indeed, the optimistic replication model is based on the replication of shared objects on multiple sites and ensures their consistency. In our context, the number of sites is unknown and varies like in P2P networks. A collaborative editing system using the optimistic replication is correct if it ensures the consistency model CCI. We propose Swooki and DSMW, two instantiations of the optimistic replication model for semantic wikis that ensure the CCI consistency of the new replicated data type. Swooki is the first P2P semantic wiki. It addresses specifically the problems of scalability and fault tolerance. While DSMW allows to build a semantic friend-to-friend network and to support collaborative editing processes.