Looks like the RIAA is suing XM Radio for a device that lets people record XM's digital broadcasts. Remember that the RIAA complained loudly that tape cassettes and home taping would kill their business back in the day. It didn't, but that didn't keep the RIAA from collecting a fee on every blank tape sold. IMHO, this is extortion.
Conceivably, anybody who subscribes to XM could use the line out jacks on and XM receiver to bring the signal to a tape deck, and make tapes of the broadcasts so that they could be listened to at any time. They could burn CDs or audio DVDs if they ported the signal to a computer or a burner. So what's different about what XM is doing?
The government is going to have to decide whether or not it wants to be in the business of preserving outdated business models.