Gnutella differs from Napster in two important ways. First, it allows users to swap any type of file, while Napster only lets users swap MP3 music files. This has raised the concern of the Motion Picture Association of America (MPAA) because movies can be exchanged as files - albeit very large files. Second, Gnutella is decentralised, meaning there is no central server that users access to find what files they can download from other users. This means that there is no server to shut down and nobody to sue but the users themselves - or possibly ISPs.
The MPAA is said to have sent hundreds of letters to major ISPs and universities, warning them that people on their networks are breaching the Digital Millennium Copyright Act (DMCA) by trading copyrighted movies through Gnutella. Excite@Home, one of the largest ISPs in the US, has sent e-mails to a number of Gnutella users, telling them their services will be terminated within 24 hours if their alleged movie sharing continues.
Under the DMCA, an ISP must take action when it has “actual knowledge” of an infringement (by facts brought to its attention or by notice from the copyright owner), but it does not impose a burden on the ISP to monitor or discover infringing behaviour.
Excite@Home said that the MPAA provided it with evidence of the infringements. However, while monitoring of file transmissions is possible with the Gnutella system, a bigger threat to copyright owners lies in Freenet. Freenet is free software similar to Gnutella, but the identity of Freenet users and the files they transfer are said to be impossible to identify. Accordingly, it may be impossible for bodies like the MPAA to present any evidence to ISPs that their users are in breach of copyright laws.