The Supreme Court just handed down a decision in MGM v Grokster. The ruling, as quoted on Slashdot, said: "One who distributes a device with the object of promoting its use to infringe copyright ... is liable for the resulting acts of infringement by third parties using the device, regardless of the device's lawful uses."
They also sent the case back to the lower court to be retried, so more on this will certainly be forthcoming. (Of course, if I worked at Grokster, I'd be getting my resume ready.)
I'm curious how this will effect the Betamax decision. VCRs are promoted as copying devices. So are computers. Much copying these days infringes.
More on this as I understand it better.