Napster fell.  Kazaa fell.  And now the RIAA is waging an all out war to try to ensure Limewire follows in its P2P ancestors' footsteps.

Even as the move industry turns its efforts to suing thousands of BitTorrent users, the music industry is waging its own hard-fought war against filesharers.  After a long and unprofitable legal crusade, the RIAA has largely turned its efforts to lobbying the government to take up the mantle of tracking and prosecuting filesharers.

With the upcoming Anti-Counterfeiting Trade Agreement the RIAA may have scored its biggest victory -- making it a felony crime to develop P2P engines that become used to distribute infringed content.

Not content to wait for the vote on that measure, music labels have taken the fight to one of the most-downloaded filesharing engines, Limewire.  Since the descent of Napster and Kazaa into legal and financial purgatory, Limewire has emerged as perhaps the most recognizable P2P engine.

The RIAA -- the music industry attack dog -- sue Limewire for $150,000 per infringed song way back in 2006.  However, LimeWire founder Mark Gorton had frustrated the labels for almost four years.  In May the labels secured a major victory -- a summary judgment against Limewire for copyright infringement, engaged in unfair competition, and induced copyright infringement.

Last month the RIAA accused Gorton of shifting his money to avoid paying damages from the case.  They have appealed to the courts to try to have his assets frozen.  They also filed a motion to have Limewire's services shut down.

Now a coalition of four major labels -- EMI, Sony/ATV, Universal and Warner/Chappell -- and four independent labels -- Bug, MPL, Peermusic and the Richmond Organization -- have filed a brand new suit against the popular program.  Represented by the National Music Publishers’ Association (NMPA), the labels filed suit in Southern District Court in Manhattan on Wednesday.  

In the suit, they also seek $150,000 USD per song distributed -- the maximum for willful infringement.  Limewire constitutes 58 percent of the P2P traffic online, according to the NPD Group.  Limewire software has been downloaded 200 million times, including over 340,000 downloads in the last week.

Limewire has a legal music store, which offers over 2 million DRM-free tracks for sale.  However, the service is also thought to host well over a million infringed tracks.  That puts a conservative estimate of the amount sought in the new suit at $150B USD.

Even with Limewire's dominant position in the P2P industry there's no way it could pay that much in damages, as its assets sit in the millions, not billions.  It's hard to say what will happen in the case, but things thus far are clearly not going Limewire's way.

Ultimately one possibility would be a settlement, which would allow Limewire's music store to stay open and continue paying damages to the RIAA and NMPA (the two groups that have filed suit).  It remains to be seen, though, whether users would stick with the service if it went legit or leave it, as has traditionally happened throughout filesharing history (with services such as Kazaa and Napster).