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File sharing usually follows the peer-to-peer (P2P) model, where the files are stored on and served by personal computers of the users. Most people who engage in file sharing on the Internet both provide (upload) files and receive files (download).
P2P file sharing is distinct from file trading in that downloading files from a P2P network does not require uploading, although some networks either provide incentives for uploading such as credits or forcing the sharing of files being currently downloaded. Napster started this whole wave and has since became a legal spot for downloads with a fee schedule.
The first generation of peer-to-peer file sharing networks had a centralized file list. In the centralized peer-to-peer model, a user would send a search to the centralized server of what they were looking for. The server then sends back a list of peers that have the data and facilitates the connection and download.
The first file-sharing programs marked themselves by inquiries to a server, either the data to the download held ready or in appropriate different Peers and so-called Nodes further-obtained, so that one could download there. Two examples were Napster (today using a pay system) and eDonkey2000 in the server version (today, likewise with Overnet and KAD - network decentralized).
Webhosting is also used for file sharing, since it makes it possible to exchange privately. In small communities popular files can be distributed very quickly and efficiently. Web hosters are independent of each other; therefore contents are not distributed further. Other terms for this are one-click hosting and web-based sharing.
Recently, Facebook opened up its API to 3rd party developers that has allowed for a new type of file-sharing service to emerge. Box.net and FreeDrive.com [1] are two examples of companies that have specific Facebook Applications that allow file sharing to be easily accomplished between friends.
After Napster encountered legal troubles, Justin Frankel of Nullsoft set out to create a network without a central index server, and Gnutella was the result. Unfortunately, the Gnutella model of all nodes being equal quickly died from bottlenecks as the network grew from incoming Napster refugees. FastTrack solved this problem by having some nodes be \'more equal than others\'.
By electing some higher-capacity nodes to be indexing nodes, with lower capacity nodes branching off from them, FastTrack allowed for a network that could scale to a much larger size. Gnutella quickly adopted this model, and most current peer-to-peer networks implement this design, as it allows for large and efficient networks without central servers.
Also included in the second generation are distributed hash tables (DHTs), which help solve the scalability problem by electing various nodes to index certain hashes (which are used to identify files), allowing for fast and efficient searching for any instances of a file on the network. This is not without drawbacks; perhaps most significantly, DHTs do not directly support keyword searching (as opposed to exact-match searching).
The best examples are Gnutella, Kazaa or eMule with Kademlia, whereby Kazaa has still a central server for logging in. eDonkey2000/Overnet, Gnutella, FastTrack and Ares Galaxy have summed up approx. 10.3 million users (as of April 2006, according to slyck.com). This number does not necessarily correspond to the actual number of persons who use these networks; it must be assumed that some use multiple clients for different networks.
Multi-Network-Clients
Further networks or clients
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All or part of this article may be confusing or unclear. Please help clarify the article. Suggestions may be on the talk page. (January 2007) |
The third generation of peer-to-peer networks are those that have anonymity features built in. Examples of anonymous networks are ANts P2P, RShare, Freenet, I2P, GNUnet and Entropy.
A degree of anonymity is realized by routing traffic through other users\' clients, which have the function of network nodes. This makes it harder for someone to identify who is downloading or who is offering files. Most of these programs also have strong encryption to resist traffic sniffing.
Friend-to-friend networks only allow already-known users (also known as "friends") to connect to the user\'s computer, then each node can forward requests and files anonymously between its own "friends" nodes.
Third-generation networks have not reached mass usage for file sharing because most current implementations incur too much overhead in their anonymity features, making them slow or hard to use. However, in countries where very fast fiber-to-the-home Internet access is commonplace, such as Japan, a number of anonymous file-sharing clients have already reached high popularity.
An example might be: Petra gives a file to Oliver, then Oliver gives the file to Anna. Petra and Anna thus never become acquainted and thus are protected. Often used virtual IP addresses obfuscate the user\'s network location because Petra only knows the virtual IP of Anna. Although real IP\'s are always necessary to establish a connection between Petra and Oliver, nobody knows if Anna really requested and Petra really send the file or if they just forward it (As long as they won\'t tell anyone their virtual IP\'s!). Additionally all transfers are encrypted, so that even the network administrators cannot see what was sent to whom. Example software includes WASTE, JetiANts, Tor and I2P. These clients differ greatly in their goals and implementation. WASTE is designed only for small groups and may therefore be considered Darknet; ANts and I2P are public Peer-to-Peer systems, with anonymization provided exclusively by routing reach.
Ants network
Mute network
I2P network
Retroshare-Network (F2F Instant Messenger)
other networks or clients
Apart from the traditional file sharing there are services that send streams instead of files over a P2P network. Thus one can hear radio and watch television without any server involved -- the streaming media is distributed over a P2P network. It is important that instead of a treelike network structure, a swarming technology known from BitTorrent is used. Best examples are Peercast, Miro, Cybersky and demo TV.
General
Tree structure
Swarm structure such as BitTorrent
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Since illegally downloading files has become more common, there has been much controversy about whether infringement of copyrighted music has either hurt or helped CD sales.
Some economic studies have found that file sharing has a negative impact on record sales. For example, three papers published in the April 2006 issue of the Journal of Law and Economics (Liebowitz, Rob and Waldfogel, Zentner) all found harm from filesharing.
As Alejandro Zentner demonstrated in his study conducted in 2005 Topics in Economic Analysis & Policy, music sales have globally dropped from approximately $38 billion in 1999 to $32 billion in 2003, noting that the downward trend coincides with the advent of Napster in June of 1999. Additionally, in another study performed by Zentner in 2003 Measuring the Effect of Music Downloads on Music Purchases, he points out by his calculations that music sales in the countries included in the study would be 7.8 percent higher in 2002 if file-sharing did not exist.
In 2006, Stan J. Liebowitz, a professor of economics at University of Texas at Dallas published an article examining file-sharing and the impact it has on music sales (Economists Examine File-Sharing and Music Sales). In this article, Liebowitz (2006) examines several studies that show a decline in album sales per capita due to an increase in downloading music. One study (Liebowitz, 2005) looks at “the sales of CDs in 99 US cities by the number of individuals in various age groups within a city both with and without Internet access. Using Internet access as a proxy for file-sharing, he finds that large young populations with Internet access reduce record sales. The coefficients are of sufficient size to support a conclusion that file-sharing could explain the entire decline in sales.” The article further demonstrates these findings by citing a study done by Peitz and Waelbroeck in 2004, which used data from 16 countries between the years 1998-2002. They found a 20% decline in the sales of music worldwide. Zentner (2004) uses international cross-section data from a very large number of countries during the period 97-98 to 2001-2002. He finds a worldwide decline of 15% and a US decline of 30% (16-17).
Liebowitz offers further possible explanations for a decline in music sales regarding music sales. For instance, he states that “such a large change would be caused by either an unusually powerful but established factor, an unusual confluence of established factors, or some completely new factor.” He suggests that file-sharing programs such as Napster, which was the forerunner of modern file-sharing, offered a new way for consumers to obtain music files and although Napster shut down in 2001, file-sharers began migrating to other file-sharing services. Liebowitz concluded this section with the statement that “The confluence of file-sharing’s birth and the decline in record sales, the rapid growth to an immense size of file-sharing activities, and the unusually large decline in the sound recording market are all consistent with a claim that file-sharing is responsible for the decline in sales" (15).
Finally, Liebowitz proposes several alternative explanations as potential explanations for the overall decline in music sales, such as price and income changes (21), the impact that substitutes such as DVDs had on music sales (23-24), and lower quality of music in general (25).
However, the most widely cited paper concludes that file sharing has no negative effect on CD sales. This paper by Olberholzer-Gee and Strumpf,http://www.utdallas.edu/~liebowit/intprop/OS%202006-12-12.pdf was published in the February 2007 issue of the Journal of Political Economy, and is the only paper which analyzes actual downloads on file sharing networks. As staff writer John Borland of CNET News.com reports, “even high levels of file-swapping seemed to translate into an effect on album sales that was ‘statistically indistinguishable from zero,’ they [the researchers] wrote.” By “John Borland”, See [2]. From data gathered from the many weeks of tracking downloading on OpenNap servers they found that most users logged on very rarely and when they did log on they only downloaded a little more than one CD’s worth of songs. To show how these downloads affected album sales they tracked sales and downloads of 500 random albums of varying genres and after doing so found that illegal downloads would only be a small force in the decrease in album sales, possibly even slightly improving album sales of the top albums in stores at the time. By “John Borland”, See [3].
Some researchers believe that massive copying has been occurring ever since the invention of tape cassettes and the increased economic impact of simpler access to copying provided by computer networks does not seem to have been large.[citation needed].
According to an article published by the Almighty Institute of Music Retail, an estimation of 900 independent record stores have closed since 2003, leaving 2,700 nationwide. Carolyn Draving, the owner of Trac Records is being closed after 32 years and she believes the downfall is a direct result of the illegal internet. She states that she lost many long-time consumers to the internet and knows for certain that a few stopped coming in because they just downloaded instead. Another owner, Warren Greene of Spinsters Records claims that nobody buys CD’s anymore and that most of his customers have turned to the internet in order to obtain their music.
In order to keep these smaller record stores alive, owners are having to find alternative means to stay afloat. Greene has saved his store from going under “...by finding a new product to sell: T-shirts emblazoned with digital images.”By “John Wilen”, See Almighty Institute of Music Retail. He purchased a digital garment printing machine that lets him print any digital photo a customer wants onto a T-shirt. The shirts sell for $20 to $25, and are creating a higher profit margin then the sale of CD’s.
An article posted in the Wall Street Journal have found that CD sales have dropped 20% since last year, which they say is the latest sign of the shift in the way people acquire their music. While the music industry, along with other types of media such as film and TV are having a difficult time adapting to the digital age, BigChampagne LCC has reported that around one billion songs a month are being traded on illegal file-sharing networks. As a result of this decline in CD sales, a significant amount of record stores are going out of business and “...making it harder for consumers to find and purchase older titles in stores.” By “Ethan Smith”, See Wallstreet Journal Website.
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This section may require cleanup to meet Wikipedia\'s quality standards. Please improve this article if you can (October 2007). |
File sharing grew in popularity with the proliferation of high-speed Internet connections, and the relatively small file size and high-quality MP3 audio format. Although file sharing is a legal technology with legal uses, many users use it to download and upload copyrighted materials without permission, which can be copyright infringement if done without authorization for improper purposes. Despite the existence of various international treaties, there are still sufficient variations between countries to cause significant difficulties in the protection of copyright. This has led to attacks against file sharing in general from many copyright owners and litigation by industry bodies against private individual sharers. The legal issues surrounding file sharing have been the subject of debate and conferences, especially among lawyers in the entertainment industries. [4] The challenges facing copyright holders in the face of file-sharing systems are quite novel historically and have highlighted many new challenges in both theory and practice:
Further challenges have arisen because of the need to balance self-protection against fair use. A perceived overbalance towards protection (in the form of media that cannot be backed up, cannot be played on multiple systems by the owner, or contains rootkitsSee 2005 Sony BMG CD copy protection scandal. or irksome security systems inserted by manufacturers) has led to a backlash against protection systems in some quarters. For example, the first crack of AACS was inspired by a perceived unfair restriction on owner usage.By "Muslix64", written on doom9\'s forum. See original post and the ensuing AACS encryption key controversy.
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According to a poll, 75% of young voters in Sweden (18-20) support filesharing, even if it is illegal when presented to the statement:
| “ | I think it is OK to download files from the Net, even if it is illegal | ” |
38% said they "adamantly agreed" while 39% said they "partly agreed".The Local - Young voters back file sharing
Many peer-to-peer networks are under constant attack by people with a variety of motives.
Examples include:
Some file-sharing software comes bundled with malware such as spyware, viruses, adware, or otherwise privacy-invasive software. Sometimes this unwanted software remains installed on the system even if the original file-sharing software is removed, and can be very difficult to eliminate. In many cases such malware can interfere with the correct operation of web browsers, anti-virus software, anti-spyware and software firewalls; can cause degraded performance on affected systems; and in some cases may secretly compromise a user\'s privacy or security. Malware is typically bundled with proprietary software, and not those in open source. In most cases it is possible to remove adware and spyware by running spyware removal programs. Such programs can often remove malware without influencing the functionality of the file-sharing software.
Some are also concerned about the use of file-sharing systems to distribute adult pornography to children, child pornography to anyone, inflammatory literature, and illegal or "unpopular" material. Novice users may find it difficult to obtain information about which networks, if any, are "safe" for them to use. With experience, users can reduce their exposure to offensive material by structuring their searches carefully (for example, a search limited to audio file types avoids exposure to video and image files).Morris, Alan (2003-08-22). Testimony of Mr. Alan Morris about Pornography, Technology and Process: Problems and Solutions on Peer-to-Peer Networks. United States Senate, Committee on the Judiciary, Washington, DC. Retrieved on 2006-11-20.
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