The Recording Industry Ass. of America (RIAA) has told seven P2P software companies to get with the programme - or face the consequences.

The organisation, infamous for the thousands of lawsuits it has issued against alleged file-sharers, said it has asked the firms to shut down their networks or implement RIAA-approved anti-piracy measures.

The RIAA hasn't said which P2P networks it sent cease and desist letters to, but the Wall Street Journal yesterday named LimeWire, BearShare and WinMX, and it's not hard to guess who the others might be.

The demands come three months after the US Supreme Court ruled that P2P providers Grokster and StreamCast are responsible for the actions of their users. If P2P users share content without the permission of the copyright holder then they're guilty of copyright infringement and so too are networks that did nothing to stop them, the Supreme Court said in June.

The verdict reversed judgements made at the District Court and Court of Appeal levels, which were founded on the precedent established in a landmark case brought in the 1980s by the movie industry against Sony. Back then, the Japanese giant prevailed, by showing its video recorders had plenty of uses beyond illegally copying movies. This time round, the P2Pers made the same claims, but the Supreme Court maintained that there were substantial differences between the two cases, so the Sony precedent does not apply.

The case now returns to the lower court, which must now re-consider the movie industry's complaint against Grokster and StreamCast in the light of the Supremes' decision.

The RIAA claimed the Supreme Court judgement had given P2P companies notice "there is a right way and a wrong way to conduct a business", and in the intervening months they have been granted "ample opportunity to do the right thing". It said firms that continue to allow users to share and download illegal copies, and "knowingly operate on the wrong side of that line do so at their own risk".

LimeWire, for one, now asks anyone downloading their software if they intend to infringe copyright, refusing to offer the software to anyone who foolishly checks the 'yes' option. That may appease the RIAA, but we doubt it - there are plenty of copies of the code out there already, and when we checked this afternoon, still rather a lot of illicit material to grab. ®