Communities of practice (CoPs), a specific form of intra-organizational networks, are increasingly regarded as important structures within organizations. Their network structure is well-suited for the development and sharing of knowledge and practices across divisions. Stefano Borzillo examines a large variety of CoPs by means of six success factors and identifies three basic types: innovating strategic, operational excellence, and social and productive space CoPs. He shows that innovating strategic CoPs are strongly sponsored by management, that operational excellence CoPs are used to multiply technical and operational practices throughout an organization, and that social and productive space CoPs owe their success to their members’ sense of security.