Companies which make programs to allow file swapping over the internet have won a rare court victory in the Netherlands.

A Dutch appeal court has ruled in favour of KaZaA and against a music rights organisation, Buma Stemra, allowing the company to distribute its software.

The court overturned an earlier injunction, ruling that even if users chose to breach the copyright on music and films by uploading copies to the internet using KaZaA, that was not the company's problem.

Niklas Zennstrom, KaZaA's Swedish founder, noted that the ruling was too late to save KaZaA, most of whose assets were sold last year to an Australian company.

But he said the decision was "a great victory for our company and the whole technology sector".

Right or wrong

Proponents of file-swapping such as Mr Zennstrom say efforts by music and film companies to stamp out file-swapping stomp all over users' legitimate rights.

If piracy is taking place, they say, the companies should chase the pirates, since file-swapping has myriad entirely legal uses.

But the industry disagrees.

"We are stunned by the verdict," a Buma Stenra spokesman said. A further appeal is possible.

Fight to the death

The ruling stands in stark contrast to most of the court battles over the sometimes conflicting rights of users of copyrighted material and their creators - or, rather, the music and film companies which distribute them.

The US grand-daddy of the file-swapping world, Napster, was almost driven out of business, and is now back with a much less popular pay-per-download system.

The main systems for swapping files - in the past generally MP3 music files but nowadays TV and movie-sourced video files - no longer suffer from Napster's big Achilles' Heel, which was that the lists on its servers allowed users to copy illegally data stored on other people's computers.

Morpheus MusicCity, KaZaA and the latter's US peer, Grokster, all enable "peer-to-peer" swapping, where the files are distributed around users' computers and don't need lists on a central server to bring the two together.

But they are still facing heavy-handed lawsuits from the entertainment industry.