A Community of Practice (CoP) unites individuals with shared interests and shared or complementary competencies to interact on a regular basis, advancing communal learning and knowledge. By facilitating increased, relevant interactions between people, CoPs often improve organizational effectiveness. They can be initiated as a performance improvement intervention at the individual, group and organizational levels. After describing the theoretical background of CoPs as discussed in the organizational theory and knowledge management literature, this article classifies the results of research in the knowledge management domain, dating from 1991, into an actionable Plan-Do-Check-Act (PDCA) model. Future trends in CoP development, including e-Science and digital ecosystems, are then discussed.