The term "peer-to-peer" has come to be applied to networks that expect end users to contribute their own files, computing time, or other resources to some shared project. Even more interesting than the systems technical underpinnings are their socially disruptive potential: in various ways they return content, choice, and control to ordinary users. While this book is mostly about the technical promise of peer-to-peer, we also talk about its exciting social promise. Communities have been forming on the Internet for a long time, but they have been limited by the flat interactive qualities of email and Network newsgroups. People can exchange recommendations and ideas over these media, but have great difficulty commenting on each others postings, structuring information, performing searches, or creating summaries. If tools provided ways to organize information intelligently, and if each person could serve up his or her own data and retrieve others data, the possibilities for collaboration would take off. Peer-to-peer technologies along with metadata could enhance almost any group of people who share an interest--technical, cultural, political, medical, you name it. This book presents the goals that drive the developers of the best-known peer-to-peer systems, the problems theyve faced, and the technical solutions theyve found. Learn here the essentials of peer-to-peer from leaders of the field: Nelson Minar and Marc Hedlund of target="new">Popular Power, on a history of peer-to-peer Clay Shirky of acceleratorgroup, on where peer-to-peer is likely to be headed Tim OReilly of OReilly & Associates, on redefining the publics perceptions Dan Bricklin, cocreator of Visicalc, on harvesting information from end-users David Anderson of SETI@home, on how SETI@Home created the worlds largest computer Jeremie Miller of Jabber, on the Internet as a collection of conversations Gene Kan of Gnutella and GoneSilent.com, on lessons from Gnutella for peer-to-peer technologies Adam Langley of Freenet, on Freenets present and upcoming architecture Alan Brown of Red Rover, on a deliberately low-tech content distribution system Marc Waldman, Lorrie Cranor, and Avi Rubin of AT&T Labs, on the Publius project and trust in distributed systems Roger Dingledine, Michael J. Freedman, andDavid Molnar of Free Haven, on resource allocation and accountability in distributed systems Rael Dornfest of OReilly Network and Dan Brickley of ILRT/RDF Web, on metadata Theodore Hong of Freenet, on performance Richard Lethin of Reputation Technologies, on how reputation can be built online Jon Udell ofBYTE and Nimisha Asthagiri andWalter Tuvell of Groove Networks, on security Brandon Wiley of Freenet, on gateways between peer-to-peer systems Youll find information on the latest and greatest systems as well as upcoming efforts in this book.