Copyright companies are pitted against technology manufacturers; conservative Christians are allied with Hollywood; government agencies at all levels are opposing venture capitalists. Here's a quick guide to some of the key players in the debate, what they've said, and why they care.
Copyright holders: The Recording Industry Association of America (RIAA), the Motion Picture Association of America (MPAA), and the National Music Publishers Association (NMPA) have been trying to force file-swapping software companies out of business since Napster's rise.
The RIAA blames rampant file-swapping in part for the substantial decline in music sales worldwide over the past four years, and says services such as Grokster are unfair competition for legal stores like iTunes. There's little sign that Hollywood's revenues are going down, but the MPAA says studios lost $3.5 billion to physical piracy in 2004, which doesn't even count the huge numbers of movies being swapped online.
All three groups are pressing for either a court or a legislative solution that would let them sue file-swapping companies, but for the last year, the RIAA and MPAA have instead turned their legal guns on individuals.
U.S. government: The Solicitor General's office joined the copyright holders on the floor of the Supreme Court, arguing that intellectual-property protection was critical to the U.S. economy. The office proposed modifying existing law to say that if a product is "overwhelmingly used" for infringement, and if a business depends on those illicit uses, then the company ought to be held liable.
Grokster, StreamCast Networks: The two companies that prompted the lawsuit, along with Kazaa parent Sharman Networks (which has been left in lower courts, following jurisdictional disputes).
Both companies produced software that was used to create decentralized file-swapping networks, eschewing the original Napster's ongoing role as a facilitator of searches and swaps. Two lower courts said that was enough to relieve them of responsibility for actions of people using their software.
At the time of the original lawsuit, Streamcast Networks' Morpheus was on its way to becoming the most popular file-swapping software in the world. It was replaced almost overnight by Kazaa, which in turn has now been eclipsed by eDonkey.
Electronic Frontier Foundation: The San Francisco-based EFF has provided key legal and intellectual support for file-swapping software companies throughout the Grokster case. The group agreed to represent Streamcast Networks not long after that company was sued by copyright holders, contending that the lawsuit was different in critical ways than the Napster case.
Lawyers for the EFF have consistently argued that peer to peer is a general-use technology--like computers. By targeting companies that released software and then had no further direct interaction with users, the record labels and movie studios threatened innovation and digital rights well beyond peer to peer, the EFF argued.
From the sidelines
Silicon Valley: Led by Intel and venture capitalists, technology leaders have been deeply worried that any changes to the 1984 Sony Betamax decision could undermine their business. That case, which protected the sale of any device that has "substantial noninfringing uses," has been critical to the production and distribution of products from the CD burner to the iPod to the personal computer itself.
Consumer groups: Consumers Union and the Consumer Federation of America have spoken out sharply in favor of file-swapping software companies, saying that peer-to-peer software can be used for protected political speech and can have benefits to consumers. The groups stop short of endorsing copyright infringement, but they've said consumer behavior can be explained by record labels' "anticompetitive" behavior.
Consumer electronics companies: The Consumer Electronics Association has played one of the most visible roles in challenging the copyright holders, all the way up to arranging for protesters holding "Save Betamax" signs in front of the Supreme Court on the day of the Grokster hearing. The group's companies are deeply indebted to the Betamax decision and argue vociferously that anything merely "capable of substantial noninfringing use" remain legal.
State attorneys general: A group of 39 state attorneys general petitioned the court in favor of the copyright holders, saying that the unrestricted P2P services were encouraging innovation that ignores, and therefore encourages, lawlessness. They say P2P companies that deliberately construct their networks to prevent themselves from seeing infringement--which they know exists in huge quantities--should be held liable.
Christian Coalition: An odd pairing if ever there was one. The conservative Christian organization and several allies joined the cause of Hollywood and the record labels, saying that the lower courts' decisions could lead to a proliferation of anonymous, untraceable child pornography.
Institute of Electronics and Electrical Engineers: The IEEE petitioned the court without supporting either side, saying that courts had strayed from traditional intellectual-property rules in recent years. In an argument that several Supreme Court justices initially appeared deeply sympathetic to, the group argued that products having substantial noninfringing uses should be legal, unless their parent companies actively induced customers to act illegally.