Peer-to-peer file sharing
Peer-to-peer file sharing is the distribution and sharing of digital media using peer-to-peer networking technology. P2P file sharing allows users to access media files such as books, music, movies, and games using a P2P software program that searches for other connected computers on a P2P network to locate the desired content. The nodes of such networks are end-user computers and distribution servers.
In the early days of file-sharing, transfers occurred predominantly via client-server downloads from web pages, FTP, and IRC before Napster popularised a Windows application that allowed users to upload and download with a freemium-style service. Record companies and artists called for its shutdown and FBI raids followed. Napster had been incredibly popular at its peak, spawning a grass-roots movement following from the mixtape scene of the 80's and left a significant gap in music availability with its followers. After much discussion on forums and in chat rooms, it was decided that Napster had been vulnerable due to its reliance on centralised servers and their physical location and thus competing groups raced to build a decentralised peer-to-peer system.
Peer-to-peer file sharing technology has evolved through several design stages from the early networks like Gnutella, which popularized the technology in several iterations that used various front ends such as Kazaa, LimeWire and WinMX before Edonkey then on to later models like the BitTorrent protocol. Microsoft uses it for Update distribution and online video games use it as their content distribution network for downloading large amounts of data without incurring the dramatic costs for bandwidth inherent when providing just a single source.
Several factors contributed to the widespread adoption and facilitation of peer-to-peer file sharing. These included increasing Internet bandwidth, the widespread digitization of physical media, and the increasing capabilities of residential personal computers. Users are able to transfer one or more files from one computer to another across the Internet through various file transfer systems and other file-sharing networks.
History
The central index server indexed the users and their shared content. When someone searched for a file, the server searched all available copies of that file and presented them to the user. The files would be transferred directly between private computers. A limitation was that only music files could be shared. Because this process occurred on a central server, however, Napster was held liable for copyright infringement and shut down in July 2001. It later reopened as a pay service.After Napster was shut down, peer-to-peer services were invented such as Gnutella and Kazaa. These services also allowed users to download files other than music, such as movies and games.
Technology evolution
and eDonkey2000 both used a central server-based model. These systems relied on the operation of the respective central servers, and thus were susceptible to centralized shutdown. Their demise led to the rise of networks like Limewire, Kazaa, Morpheus, Gnutella, and Gnutella2, which are able to operate without any central servers, eliminating the central vulnerability by connecting users remotely to each other. However, these networks still relied on specific, centrally distributed client programs, so they could be crippled by taking legal action against a sufficiently large number of publishers of the client programs. Sharman Networks, the publisher of Kazaa, has been inactive since 2006. StreamCast Networks, the publisher of Morpheus, shut down on April 22, 2008. Limewire LLC was shut down in late 2010 or early 2011. This cleared the way for the dominance of the BitTorrent protocol, which differs from its predecessors in two major ways. The first is that no individual, group, or company owns the protocol or the terms "Torrent" or "BitTorrent", meaning that anyone can write and distribute client software that works with the network. The second is that BitTorrent clients have no search functionality of their own. Instead, users must rely on third-party websites like Isohunt or The Pirate Bay to find "torrent" files, which function like maps that tell the client how to find and download the files that the user actually wants. These two characteristics combined offer a level of decentralization that makes BitTorrent practically impossible to shut down. File-sharing networks are sometimes organized into three "generations" based on these different levels of decentralization. Darknets, including networks like Freenet, are sometimes considered to be third-generation file-sharing networks.Peer-to-peer file sharing is also efficient in terms of cost. The system administration overhead is smaller because the user is the provider and usually the provider is the administrator as well. Hence each network can be monitored by the users themselves. At the same time, large servers sometimes require more storage and this increases the cost since the storage has to be rented or bought exclusively for a server. However, usually peer-to-peer file sharing does not require a dedicated server.
Economic impact
There are ongoing discussions about the economic impact of P2P file sharing. Norbert Michel, a policy analyst at The Heritage Foundation, said that studies had produced "disparate estimates of file sharing's impact on album sales".In the book The Wealth of Networks, Yochai Benkler states that peer-to-peer file sharing is economically efficient and that the users pay the full transaction cost and marginal cost of such sharing even if it "throws a monkey wrench into the particular way in which our society has chosen to pay musicians and recording executives. This trades off efficiency for longer-term incentive effects for the recording industry. However, it is efficient within the normal meaning of the term in economics in a way that it would not have been had Jack and Jane used subsidized computers or network connections".
A calculation example:
with peer to peer file sharing:
with casual content delivery networks:
Music industry
The economic effect of copyright infringement through peer-to-peer file sharing on music revenue has been controversial and difficult to determine. Unofficial studies found that file sharing had a negative impact on record sales. It has proven difficult to untangle the cause and effect relationships among a number of different trends, including an increase in legal online purchases of music; illegal file-sharing; drop in the prices of compact disks; and the closure of many independent music stores with a concomitant shift to sales by big-box retailers.Film industry
The Motion Picture Association reported that American studios lost $2,373 billion in 2005 representing approximately one third of the total cost of film piracy in the United States. The MPAA's estimate was doubted by commentators since it was based on the assumption that one download was equivalent to one lost sale, and downloaders might not purchase the movie if illegal downloading was not an option. Due to the private nature of the study, the figures could not be publicly checked for methodology or validity. In January 2008, as the MPAA was lobbying for a bill which would compel Universities to crack down on piracy, it was admitted by MPAA that its figures on piracy in colleges had been inflated by up to 300%.A 2010 study, commissioned by the International Chamber of Commerce and conducted by independent Paris-based economics firm TERA, estimated that unlawful downloading of music, film and software cost Europe's creative industries several billion dollars in revenue each year. A further TERA study predicted losses due to piracy reaching as much as 1.2 million jobs and €240 billion in retail revenue by 2015 if the trend continued. Researchers applied a substitution rate of ten percent to the volume of copyright infringements per year. This rate corresponded to the number of units potentially traded if unlawful file sharing were eliminated and did not occur. Piracy rates for popular software and operating systems have been common, even in regions with strong intellectual property enforcement, such as the United States or the European Union.
Public perception and usage
In 2004, an estimated 70 million people participated in online file sharing. According to a CBS News poll, nearly 70 percent of 18- to 29-year-olds thought file sharing was acceptable in some circumstances and 58 percent of all Americans who followed the file sharing issue considered it acceptable in at least some circumstances. In January 2006, 32 million Americans over the age of 12 had downloaded at least one feature-length movie from the Internet, 80 percent of whom had done so exclusively over P2P. Of the population sampled, 60 percent felt that downloading copyrighted movies off the Internet did not constitute a very serious offense, however 78 percent believed taking a DVD from a store without paying for it constituted a very serious offense.In July 2008, 20 percent of Europeans used file sharing networks to obtain music, while 10 percent used paid-for digital music services such as iTunes. In February 2009, a survey undertaken by Tiscali in the UK found that 75 percent of the English public polled were aware of what was legal and illegal in relation to file sharing, but there was a divide as to where they felt the legal burden should be placed: 49 percent of people believed P2P companies should be held responsible for illegal file sharing on their networks and 18 percent viewed individual file sharers as the culprits.
According to an earlier poll, 75 percent of young voters in Sweden supported file sharing when presented with the statement: "I think it is OK to download files from the Net, even if it is illegal." Of the respondents, 38 percent said they "adamantly agreed" while 39 percent said they "partly agreed". An academic study among American and European college students found that users of file-sharing technologies were relatively anti-copyright and that copyright enforcement created backlash, hardening pro-file sharing beliefs among users of these technologies.