This morning the United States Supreme Court ruled unanimously that internet P2P file sharing services may be sued by production studios for the actions of their users, a ruling that could all but eliminate file sharing networks such as the case's defendant, Grokster. The ruling was one of the most closely watched technology cases since 1984, when the legality of video cassette tape recorders was established.
The core argument of the defendants was that while certain people use their software for illegal purposes, their product had a wide array of pratical, seemingly legal uses, such as businesses and researchers sharing files. However, Grokster did admit that their uses did commit "widespread" copyright infringement.
The ruling came down to whether or not technology may remain legal if its users used it for illegal purposes, and answer was an emphatic no.
News source: mediaweek.com