Downloading and streaming are client-server technologies. Both involve a central ``server'' that stores the audio data and delivers it to a software ``client'' running on a user's computer. With a client-server system, the data is under the complete control of the central server; the server controls what is distributed and who is able to access it. This central control in the client-server model is a strength as well as a weakness. The clients are dependent on the single server's ability to handle all of the requests it receives for data. If the server is overwhelmed--or is down completely--no content can be delivered.
Peer-to-peer networks (often abbreviated ``P2P'') avoid dependence on a central server by spreading the responsibility for delivering content across the individual computers on the network. Each computer acts as a server, and the data moves laterally from peer to peer. Once an audio file has been downloaded to a computer, that computer can then make the file available for sharing with others. A peer-to-peer network draws on the computing power, bandwidth, and content of the individual computers participating in the network. If one computer is down, there is no noticeable degradation of service because the remaining computers on the network are available to fill the void.
Peer-to-peer networks are informal. All that is needed to participate is the appropriate software application, and computers join and leave the network on a whim. The number of computers sharing content changes minute by minute, so content available one day might not be available the next. The participants on the network are usually not known to each other, and they are traceable only by their network address.
The informal, amorphous nature of peer-to-peer networks make them a convenient vehicle for anonymous filesharing, and they have gained notoriety for enabling the illegal sharing of copyprotected sound recordings, videos, and films. Most of the files shared on peer-to-peer networks are copies of commercial content being distributed without the permission of the owner, and for that reason these networks have become targets for litigation by the recording and film industries. Librarians are advised not to tap into the commercial audio resources available on these networks. The networks, however, are also a rich source for nonprofessional bootleg recordings and unreleased outtakes. By no means is all of the content on P2P networks being shared illegally, but caution is advised.
The first popular peer-to-peer network was Napster, established in June 1999 by Shawn Fanning, who wrote the underlying program while a student at Northeastern University in Boston.4.2 Napster became especially popular with college students, who were able to take advantage of fast broadband campus networks for speedy, efficient filesharing. In December 1999, the recording industry, alarmed that tens of thousands of copyprotected files were being shared free of charge through Napster, pursued legal action against the company, and a March 2001 injunction shut down Napster as a free file-sharing service.4.3
The recording industry's ongoing attempts to shut down companies that develop and distribute filesharing programs has led to a game of cat and mouse; as soon as Napster was gone, filesharers moved to other platforms, and despite aggressive legal action by the recording industry--not only against the developers of peer-to-peer software but against individual filesharers--their popularity continues unabated. As of the end of 2005, the four most popular peer-to-peer filesharing networks are eDonkey, BitTorrent, FastTrack, and Gnutella, and each network can be accessed through a number of software clients.
Filesharing accounts for the majority of data traffic on the internet, and since 2005, movies and videos have surpassed music as the most popular content shared. A 2005 study of global internet traffic by CacheLogic showed that 60 percent of all internet traffic is the product of filesharing, and of the files shared on the four major platforms, 62 percent were video and only 11 were audio.4.4
Although peer-to-peer networks have little--if any--application in a library setting, they have been of great interest to the library community for the intellectual property challenges they have raised. In fact, most of the litigation involving digital audio and video has centered on attempts to curb filesharing. In 2005, the Supreme Court ruled unanimously that Grokster (the developer of software used with the FastTrack network) could be held liable for users' copyright infringements.4.5 The future of music distribution will undoubtedly be shaped by such legal decisions as they are handed down.