Posner Opines on Grokster
Grokster relied heavily on a case that the Supreme Court had decided many years ago involving Betamax, a predecessor to the VCR. And so it is argued that file sharing of copyrighted music and film may also turn out to have unexpected benefits for the copyright owners themselves.
But the logic of this argument is that there can never be liability for contributory infringement because the possibility can never be excluded that the product or service offered by the alleged contributory infringer. There is a possible middle way that should be considered.
The Becker-Posner Blog. Grokster, File Sharing, and Contributory Infringement–Posner. July 3, 2005.