MGM Studios, Inc. v. Grokster, Ltd., 545 U.S. 913 (2005), is a United States Supreme Court decision in which the Court ruled unanimously that the defendants, peer-to-peer file sharing companies Grokster and Streamcast (maker of Morpheus), could be held liable for inducing copyright infringement by users of their file sharing software. The plaintiffs were a consortium of 28 entertainment companies, led by Metro-Goldwyn-Mayer studios. Background Entertainment industry lawsuits against new technologies that enable the copying of copyrighted content date back to the 1980s, when the movie industry sought court injunctions against the sale and use of VCRs. In Sony Corp. v. Universal City Studios, the U.S. Supreme Court ruled that a technology manufacturer cannot be held liable for its users' copyright infringement if widespread unauthorized copying is unlikely, and if the technology enables significant non-infringing uses as well. The advent of file sharing via the Internet in the late 1990s, and its enabling of easy and more widespread copying of copyrighted materials, inspired new arguments from the entertainment industry, because copying technology had progressed since the 1980s. The Sony precedent was partially modified in A&M Records v. Napster (2001), which addressed the ease of sharing music files online, and how the designers of the technology could be held liable for contributory copyright infringement and vicarious copyright infringement if such behavior was the primary use of the technology and the company benefited from it. Just a few years later, Internet technology had progressed to the point that trading large video files, including those for entire movies, had become viable via popular services including Grokster. The MGM v. Grokster case is frequently characterized as a re-examination of the issues in Sony precedent, in light of rapidly progressing technologies and consumer behaviors. MGM and the other plaintiffs argued that makers of file sharing technology should held liable for their users' copyright infringement, via the contributory and vicarious infringement doctrines. The entertainment companies appealed to the Supreme Court after losing at two lower courts. The United States District Court for the Central District of California originally dismissed the case in 2003, citing the Sony precedent. On appeal, the Ninth Circuit Court of Appeals upheld the district court's decision after acknowledging that peer-to-peer ("P2P") software has legitimate and legal uses. Computer and Internet technology companies such as Intel, and trade associations including firms such as Yahoo! and Microsoft, filed amicus curiae briefs in support of