The RIAA cleaned the streets of most P2P middlemen following a momentous, Supreme Court victory in mid-2005.  In the case of MGM v. Grokster, justices unanimously held that file-sharing firms can be found liable for knowingly encouraging and profiting from copyright infringement.  "We hold that one who distributes a device with the object of promoting its use to infringe copyright, as shown by the clear expression or other affirmative steps taken to foster infringement, is liable for the resulting acts of infringement by third parties," Justice David Souter opined.

Major labels quickly shuttered sites like Grokster, BearShare and WinMX following the decision.  Others, including Kazaa, proved more difficult to shut down, though the party eventually ended in the summer of 2006. 

But what about the now-dominant LimeWire, owned by Lime Group LLC?  The RIAA first filed against LimeWire in August of 2006, the beginning of a protracted, drawn-out legal battle. 

Over that time, billions upon billions of files have shifted hands, and Lime Group chief Mark Gorton remains adamantly defensive.  That threatens to prolong the litigation, though the RIAA recently attempted to dislodge the logjam by moving for summary judgment.  "Given the vast number of infringements that occur every day using LimeWire and the lack of a genuine issue as to any material fact, the argument for imposing secondary liability on this summary judgment motion is as powerful as it was in Grokster," the RIAA stated.