Peer-to-peer has emerged as a promising new paradigm for large-scale distributed computing. The International Workshop on Peer-to-Peer Systems (IPTPS) aimed to provide a forum for researchers active in peer-to-peer computing to discuss the state of the art and to identify key research challenges. The goal of the workshop was to examine peer-to-peer technologies, appli- tions, and systems, and also to identify key research issues and challenges that lie ahead. In the context of this workshop, peer-to-peer systems were characterized as being decentralized, self-organizing distributed systems,...