A&M Records, Inc. v. Napster, Inc., 239 F.3d 1004 (9th Cir. 2001)

Record companies and music publishers brought copyright infringement action against Napster, an Internet service that facilitated the transmission and retention of digital audio files by its users. Circuit judge held injunctive relief was proper to impose duty to provide notice of copyright status upon plaintiffs, duty on service to search for copyrighted works that were subject of notice given by plaintiffs, and courts can require ISPs to use new filtering mechanism.