- This article is about file sharing over the Internet.
For printer and file sharing as local area network service, see
shared disk access.
is the practice of distributing or
providing access to digitally stored information, such as computer
programs, multi-media (audio, video), documents, or electronic
books. It may be implemented in a variety of storage, transmission,
and distribution models. Common methods are manual sharing using
computer file server installations on computer networks
, World Wide Web
documents, and the use of distributed
While file sharing is not of itself illegal, the increasing
popularity of the mp3
music format in the late
1990s led to the release and growth of Napster
and other software that, while designed
simply to aid in the sharing of electronic files, in practice led
to a huge growth in illegal file sharing: the sharing of copyright
protected files without permission. Other popular networks include
the now-defunct Kazaa
Many file sharing networks and services, accused of facilitating
illegal file sharing, have been shut down due to litigation by
groups such as the RIAA
. During the early 2000s, the fight against
copyright infringement expanded into lawsuits against individual
users of file sharing software.
The economic impact of illegal file sharing on media industries is
disputed. Copyright holders and publishers refer to studies
concluding that unauthorized downloading of movies, music and
software is unequivocally damaging the economy, although other
studies suggest file sharing is not the primary cause of declines
in sales. Illegal file sharing remains widespread, with mixed
public opinion about the morality of the practice.
Types of file sharing
There are many options for sharing files on the Internet, one of
the most popular is peer-to-peer
networks, or P2P networks. Some of the most popular networks are
. With these
networks, the user downloads a program to their computer that
allows them to connect to the network. Then with this program the
user can search the shared media on other users’ computers and
download this media from them across the Internet. These networks
allow the sharing of any type of digital content, including songs,
DVD-quality movies, computer programs and video games.
One of the most popular ways to get very large files like movies,
computer applications, and video games is to use BitTorrent
, another type of
peer-to-peer network. With BitTorrent large media files are broken
down into smaller chunks, which are then transferred to the user
(or peer) depending on the fastest possible connection to the
missing piece; all of this is done while the user is uploading the
pieces it already has to other users. While this type of file
sharing is most popular and useful for large movies and games, it
can also be used for music, but usually users download music by the
album or artist instead of a couple of songs.
File sharing can be done with no use of peer-to-peer technologies,
for example by the use of a file
. These sometimes also provide collaboration
tools such as forums and groups, and allow links for direct
downloads to be embedded in other communications such as emails and
Files were first exchanged on removable
. Computers were able to access remote files using
filesystem mounting, bulletin
servers (1985). Internet Relay Chat
(1988) and Hotline
(1997) enabled users to
communicate remotely through chat
exchange files. The mp3
encoding, which was
standardized in 1991 and which substantially reduced the size of
audio files, grew to widespread use in the late 1990s. In 1998,
were established, the Digital Millennium Copyright
was unanimously passed, and the first mp3 player devices
were launched. MP3.com offered music by unsigned artists, and grew
to serve 4 million audio downloads daily.
was created in 1979. It is a network
that was initially based on the UUCP
for dial-up connections and has, since being transported over the
Internet, used a specialized client-server protocol, the Network News Transfer
(NNTP). Its main purpose was the exchange of text
based messages, but through attachments allows users to encode
files and distribute them to participating subscribers of Usenet newsgroups
. USENET remains one of
the largest carriers of file sharing and Internet traffic. Recently
legal challenges to P2P systems have spurred a resurgence of
Usenet. USENET has also been itself the target of legal challenges
pertaining to its use in file sharing.
In June 1999, Napster
was released. Napster
is a centralized unstructured peer-to-peer system, requiring a
central server for indexing and peer discovery. It is generally
credited as being the first peer-to-peer file sharing system. In
the Napster case, an online service provider cannot use the
"transitory network transmission" safe harbor in the DMCA
if they have control
of the network with a server. Many P2P products will, by their very
nature, flunk this requirement, just as Napster did. Napster
provided a service where they indexed and stored file information
that users of Napster made available on their computers for others
to download, and the files were transferred directly between the
host and client users after authorization by Napster. Shortly after
Records, Inc. v. Napster, Inc.
court Napster blocked all copyright content from being
, and Freenet
were released in 2000, as MP3.com and Napster were facing
, released in March,
was the first decentralized file sharing network. In the Gnutella
network, all connecting software was considered equal, and
therefore the network had no central point of failure. In July,
was released and became the first
anonymity network. In September the eDonkey2000
client and server software was
In 2001, Kazaa
for the Mac was released. Its FastTrack
network was distributed, though unlike
Gnutella, it assigned more traffic to 'supernodes' to increase
routing efficiency. The network was proprietary and encrypted, and
the Kazaa team made substantial efforts to keep other clients such
off of the
In July 2001, Napster lost in court and was shut down. This drove
users to other P2P applications and file sharing continued its
exponential growth. The Audiogalaxy Satellite client grew in
popularity, and the LimeWire
released. Until its decline in 2004, Kazaa was the most popular
file sharing program despite bundled malware
and legal battles in the Netherlands, Australia, and the United
States. In 2002, a Tokyo district court ruling shut down File Rogue
and an RIAA lawsuit effectively shut down Audiogalaxy.
From 2002 through 2003, a number of popular BitTorrent services
were established, including Suprnova.org
, and The Pirate Bay
. In 2002, the RIAA was filing
lawsuits against Kazaa users. As a result of such lawsuits, many
universities added file sharing regulations in their school
administrative codes. With the shut down of eDonkey in 2005, eMule
became the dominant client of the eDonkey network. In 2006, police
raids took down the Razorback2
server and temporarily took down The Pirate Bay. Pro-file sharing
demonstrations take place in Sweden in response to the Pirate Bay
raid. In 2009, the Pirate Bay trial
ended in a guilty verdict for the primary founders of the
As of 2009, BitTorrent via uTorrent
and the trackers & indexing
sites, Gnutella via Limewire
eDonkey network via eMule
are the most popular
networks. All most popular networks and protocols including
BitTorrent, eDonkey, Gnutella, Gnutella2, FTP and HTTP are aviable
together via Shareaza
, the open source
multinetwork client. Services like
account for much of legal music sales,
and sites like YouTube
and various one-click hosting
providers allow file
sharing through uploads to their servers.
Copyright and controversy
A significant number of people share files in a way that infringes
on the legal rights of
holders. Copyright holders have
challenged the legality of file sharing networks. This has led to
litigation by industry bodies against certain private individual
The legal issues surrounding file sharing have been the subject of
debate and conferences.
Digital rights management
is intended to curb copyright infringement by preventing file
sharing but has proved unpopular with consumers due to the
restrictive usage policies imposed.
US legal controversy
In Sony Corp.
Studios, 464 U.S. 417
the Supreme Court found that Sony's new product, the Betamax
(the first mass-market consumer videocassette recorder
), did not
subject Sony to secondary copyright liability because it was
capable of substantial non-infringing uses. Decades later, this
case became the jumping-off point for all peer-to-peer copyright
The first peer-to-peer case was A&M Records v. Napster, 239
F.3d 1004 (9th Cir. 2001). In the Napster case, the 9th Circuit
considered whether Napster was liable as a secondary infringer.
First, the court considered whether Napster was contributorily
liable for copyright infringement. To be found contributorily
liable, Napster must have engaged in "personal conduct that
encourages or assists the infringement." The court found that
Napster was contributorily liable for the copyright infringement of
its end-users because it "knowingly encourages and assists the
infringement of plaintiffs' copyrights." The court goes on to
analyze whether Napster was vicariously liable for copyright
infringement. The standard applied by the court is whether Napster
"has the right and ability to supervise the infringing activity and
also has a direct financial interest in such activities." The court
found that Napster did receive a financial benefit, and had the
right and ability to supervise the activity, meaning that the
plaintiffs demonstrated a likelihood of success on the merits of
their claim of vicarious infringement. The court denied all of
Napster's defenses, including its claim of fair use.
The next major peer-to-peer case was MGM v. Grokster, 545 U.S. 913
(2005). In this case, the Supreme Court found that even if Grokster
was capable of substantial non-infringing uses, which the Sony
court found was enough to relieve one of secondary copyright
liability, Grokster was still secondarily liable because it induced
its users to infringe.
It is important to note the concept of blame in cases such as
these. In a pure P2P network there is no host, but in practice most
P2P networks are a hybrid (see "Computer science perspective"
below). This has led groups such as the RIAA to file suit against
individual users, rather than against companies. The reason that
Napster was subject to violation of the law and ultimately lost in
court is because Napster was not a pure P2P network but instead
maintained central server. This server maintained an index of the
files currently available on the network.
Around the world in 2006, an estimated five billion songs, equating
to approximately 38,000 years in music were swapped on peer-to-peer
websites, while 509 million songs were purchased online.
In November 2009, the U.S. House of Representatives introduced the
Secure Federal File Sharing Act, which would, if enacted, prohibit
the use of peer-to-peer file-sharing software by U.S. government
employees and contractors on computers used for federal government
The economic effect of file sharing on music revenue is
controversial and difficult to determine. Music sales dropped
globally from approximately $38 billion in 1999 to $32 billion in
2003, and a number of studies have found that file sharing has a
negative impact on record sales. However, a study analyzing logs of
on file sharing networks
concludes that file sharing has no negative effect on CD
sales, and possibly would slightly improve the sales
of top albums. It may be 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;
drops in the prices of CDs; and the extinction of many independent
music stores with a concommitant shift to sales by big-box
had reported that American studios
lost $2.3 billion to Internet piracy in 2005, representing
approximately one third of the total cost of film piracy in the
United States. The MPAA's estimate has been doubted by commentators
since it is based on the assumption that one download was
equivalent to one lost sale, and downloaders might not purchase the
movie even if illegal downloading were not an option. These numbers
are further suspicious due to the private nature of the study,
which cannot be publicly checked for methodology or validity. On
January 22, 2008, as the MPAA was lobbying for a bill which would
compel universities to crack down on piracy, it was alleged that
MPAA figures on piracy in colleges were inflated by up to
rates of one-quarter or more for popular software and operating
systems are common, even in countries and regions with strong
intellectual property enforcement, such as the US or the EU.
File sharing advocates
File sharing is not always illegal, even if the works being shared
are covered by copyright
. For example,
may choose to support freeware
, or anti-copyright
, and advocate the use of file
sharing as a free promotional tool.
Some advocates claim that sharing helps the affected industry by
allowing the consumer to sample the product before spending the
money to purchase it. This, they claim, in turn generates a new fan
base as many discover artists that would be virtually impossible to
discover otherwise, thus generating more album sales. Once the
consumer is allowed to "sample" a lower-quality version, they might
decide to buy, whereas they might never have bought it had they not
been allowed to sample the media on their computer first.
Some advocates also argue that file sharing doesn't hurt people
Another pro-file sharing argument is that movie, game, and other
types of media are not seeing any drop in sales; but a rise. P2P
file sharing is only one of many factors attributed to the recent
drop in CD sales.
In the case of music, another argument is the alleged overpricing
. Many consumers feel that CDs are far too
expensive relative to decreasing costs of production. Consumers who
only want one or two songs that have not been released as singles
believe they should not have to pay the entire cost of a CD.
Some file sharers argue that the companies whose intellectual property
is being copied
are large and generate high profits, and can thus afford the
possible loss in profits.
Other advocates of file sharing believe that file sharing does not
affect artists' profits and only benefits the distribution
Many advocates adamantly believe that access to music and films is,
by its intrinsic cultural value, a right that should not be subject
to distributors' oligopoly
A further argument in favour of file sharing is that not all of its
users would buy all of the material that they download. In other
words, one illegal download will not immediately translate to one
lost sale, as many anti-piracy groups maintain.
Significant cultural sources for arguments against copyright
include the Free Software
, the pirate
and civil libertarian
groups . Rasmus Fleischer
argues that Web 2.0
has changed society so significantly that
personal behavior and business models simply make copyright law
Public perception and usage
In 2004, there were an estimated 70 million people participating 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 40 percent felt that downloading copyrighted movies and
music off the Internet constituted a very serious offense, compared
with 78 percent who felt that of taking movies and music from a
In February 2008 the LA Times Blog published results of a US campus
attitude survey which showed that 64 percent of respondents
download music regularly through file-sharing networks and other
unauthorized sources. The respondents were also asked to rate on a
1 to 7 scale "how nervous they were about being punished for
illegal downloading" (1 being "not concerned" and 7 being
"extremely concerned"), two-thirds answered 1 (43 percent) or 2 (24
percent). Only 4 percent answered 5 or 6, and none answered 7,
In July 2008, 20 percent of Europeans used file sharing networks to
obtain music, while 10 percent use paid-for digital music services
such as iTunes.
In February 2009, a Tiscali UK survey found 75 percent of the
American public polled were aware of what was legal and illegal in
relation to their file sharing. However, 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, 18 percent viewed
individual file sharers as the culprits, while 18 percent either
didn’t know or chose not to answer. In the same survey, 60 percent
of people reported downloading music because of a limited budget. A
common attitude concerning music downloading was that of ‘why
should one pay for something when they can get it for free?'
to an earlier poll, 75 percent of young voters in Sweden (18-20)
supported file sharing when presented with the statement: "I think
it is OK to download files from the Net, even if it is
Of the respondents, 38 percent said they
"adamantly agreed" while 39 percent said they "partly
Researchers have examined potential security risks including the
release of personal information, bundled spyware
, and viruses
downloaded from the network. Some proprietary file sharing clients
have included bundled malware
programs typically have
Recently, there has been a drastic increase of inadvertent P2P file
sharing of personal and sensitive information. This became evident
in 2009 at the beginning of President Obama's administration. On
February 26, 2009 the blueprints to the helicopter Marine One
were made available to the public
through a breach in security through a P2P file sharing site.
Access to this information has the potential of being detrimental
to national security.
Two days prior, the Today
show reported that more than
150,000 tax returns, 25,800 student loan applications and 626,000
credit reports were all inadvertently made available though file
Over the last six years identity theft has become more prevalent.
On July 9, 2008 there was another inadvertent revealing of vast
amounts of personal information through careless use of a P2P site.
The “names, dates of birth, and social security numbers
2,000 of the firms clients, including Supreme Court Justice Stephen Breyer
In an attempt to avoid these security leaks, current legislation in
the United States is being debated, the Informed P2P User Act.
According to this act, it would be mandatory for individuals to be
aware of the risks associated with peer-to-peer file sharing before
purchasing the software. Informed consent of the user prior to use
of these programs would be required. In addition, this act would
allow users to block and remove P2P file sharing software from
their computers at any time. The Federal Trade Commission
enforce these regulations.
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