I'm afraid the NME has got the wrong end of the stick as usual, most of the coverage of this case has actually been pretty ill-informed. Creators of P2P programs are not being held responsible for illegal file sharing for merely creating P2P software. The ruling centres around the intent behind the creation of the software and the behaviour of the softwares' creator. If it can be proven that the software was created with the intention of illegal file-sharing in mind or promoted as such, then the author will be held liable. P2P technology in itself is not illegal and has many legitimate uses. For slightly more informed (though a bit long and boring) coverage see: http://www.theregister.co.uk/2005/06/27/supremes_punt_on_grokster/

Essentially it's toothless ruling, no P2P network in it's right mind advertised themselves explicitly with the equivalent of a "STEAL CHOONS HERE" banner. There's a difference in actively encouraging copywrite infringment and just not doing anything to stamp it out.