2003),[1] was a case in which the United States Court of Appeals for the Seventh Circuit addressed copyright infringement claims brought against Aimster, concluding that a preliminary injunction against the file-sharing service was appropriate because the copyright owners were likely to prevail on their claims of contributory infringement, and that the services could have non-infringing users was insufficient reason to reverse the district court's decision.

Recording industry owners of copyrights in musical performances brought contributory and vicarious infringement action, a type of secondary liability, against a website operator called Aimster, a company similar to Napster which facilitated the swapping of digital copies of songs over the internet.

The United States District Court for the Northern District of Illinois,[4] Marvin E. Aspen, Jr., granted preliminary injunction for plaintiffs, which shut down Defendant's service until the suit was resolved, Aimster appealed from this preliminary injunction to the Court of Appeals for the Seventh Circuit.

After doing this he might designate any other registered user called a buddy, with whom he might communicate directly whenever both of them were online, and have the capability of interchanging music files.

In that case, a video reproducer machine called Betamax, the predecessor of today's videocassette recorders was at the issue.

The court believed that Betamax was not hurting the copyright owners because it was enlarging the audience for their programs, as well as advertisements.

Courts have held that defendants cannot escape the reach of these statutes by deliberately shielding themselves, from clear evidence of critical facts that are strongly suggested by the circumstances, understanding that those who behave in such manner should be treated as those who had actual knowledge.