 Chapter X Knowledge Management and Interaction in Virtual Communities Maria Chiara Caschera Institute for Research on Population and Social Policies, Italy Arianna D’Ulizia Institute for Research on Population and Social Policies, Italy Fernando Ferri Institute for Research on Population and Social Policies, Italy Patrizia Grifoni Institute for Research on Population and Social Policies, Italy Copyright © 2009, IGI Global, distributing in print or electronic forms without written permission of IGI Global is prohibited. ABsTrAcT This chapter provides a classifcation of virtual communities of practice according to methods and tools offered to virtual community members for the knowledge management and the interaction process. It underlines how these methods and tools support users during the exchange of knowledge, enable learning, and increase the user ability to achieve individual and collective goals. In this chapter virtual communi- ties are classifed in virtual knowledge-sharing communities of practice and virtual learning communi- ties of practice according to the collaboration strategy. A further classifcation defnes three kinds of virtual communities according to the knowledge structure: ontology-based VCoP; digital library-based VCoP; and knowledge map-based VCoP. This chapter also describes strategies of interaction used to improve the knowledge sharing and learning in groups and organizations. It shows how agent-based method supports interaction among community members, improves the achievement of knowledge, and encourages the level of user participation. Finally, this chapter presents the system’s functionalities that support browsing and searching processes in collaborative knowledge environments.