The history of file sharing includes revolutionary, often illegal exploits that have ultimately led to the demise of many a file sharing application. As legal concerns become more widespread, safe file sharing is a bigger and bigger concern.

Napster leads the file-sharing craze.
While file sharing existed on a smaller scale in networks and universities, Napster was the first program to make file sharing easily available to all. Created in 1999, Napster was a file sharing application that utilized a central server to organize the file swapping. When looking for a file on Napster, you might be simultaneously downloading snippets of the file from 20 different sources while uploading your own files to other users on the Napster network, all of it coordinated through a central server.

Ultimately, Napster was successfully sued for distributing copyrighted materials. Many of the individuals using Napster’s service were sharing copyright-protected music, and the Recording Industry Association of America (RIAA) filed a series of lawsuits to shut down Napster. By 2001, Napster was responsible for nearly three billion copyright violations per month. Napster was shut down by a court order, but subsequent file sharing applications learned from the Napster story.

The Gnutella network.
Gnutella was a file sharing application originally released by Nullsoft in early 2000. In light of the Napster demise, Nullsoft quickly withdrew support from Gnutella, but developers were already creating file sharing applications based on the Gnutella code. Many clients work with the Gnutella network, so users have their choice of how to access it, and the Gnutella network remains a popular method of file sharing today.

Gnutella is a decentralized network, using only computers that are online at a given time to host files, so it’s difficult for legal actions to track and prosecute individual violators. (Keep in mind that sharing copyrighted files is still illegal, though, even if it’s difficult to track violators.)

Kazaa.
The big drawback of the Gnutella network is its slowness. Kazaa was the next-generation file sharing network, and, like Gnutella, many clients supported it. Morpheus was a popular Kazaa client until an issue with developers arose, at which point it switched to Gnutella. In 2003, the RIAA began suing individual Kazaa users, and the Australian recording industry sued Kazaa in 2004. The wave of lawsuits took its toll on Kazaa. Today, Kazaa is still available as a subscription-based program, but it has many restrictions and is limited in scope.

BitTorrent.
The latest in the long line of file sharing networks is BitTorrent. With BitTorrent, you can use one of a number of file sharing applications to search for a specific file. Then you connect directly to the source computer or server to download it. It’s another decentralized file sharing system, although it can be extremely difficult to practice safe file sharing with BitTorrent. Many BitTorrent files are infected with viruses, so always use a virus scanner if you’re downloading content through a BitTorrent feed.

iTunes.
iTunes isn’t file sharing, exactly, but it’s currently one of the largest sources of online music distribution. With iTunes, users must pay for files that they download from centralized servers. However, these files are fully legal, safe to download and come with no viruses. Most of the file sharing applications and networks in the past decade have been shut down or converted to commercial applications, but iTunes does commercial file sharing the best.