In an effort to combat online piracy, entertainment industry groups all over the world are pushing censorship of The Pirate Bay website. In the Netherlands such a Pirate Bay block went into effect earlier this year, but without the desired effect. Researchers from the University of Amsterdam have now revealed that the court-ordered Pirate Bay block has had no impact on the number of BitTorrent pirates.

In January, a Dutch court ruled that Ziggo, the largest ISP in the Netherlands, and competitor XS4ALL, must block access to The Pirate Bay.

The verdict was the first to bring broad censorship to the Netherlands, much to the disappointment of the two Internet providers.

But for BREIN, the Dutch anti-piracy group that started the court case, it was a major victory.

The Hollywood-backed group had convinced the court that many subscribers of the ISPs shared films that were linked through The Pirate Bay. Among other things, the group presented data on the percentage of Ziggo and XS4ALL subscribers present in several popular BitTorrent swarms.

The assumption of BREIN and the court was that a blockade of The Pirate Bay would lower the number of infringers at the two providers, but new research from the University of Amsterdam shows that this is not the case.

Researchers from the System and Network Engineering group repeated the initial BREIN tests with new torrents that were not available prior to the blockade. If censorship is effective, this number would have declined, but the researchers found that it makes no significant difference.

“The claim that The Pirate Bay blockade by Ziggo and XS4ALL leads to a decrease of copyright infringement by their subscribers via BitTorrent transfers must be rejected. There is no significant effect of this measure,” the researchers conclude.

% of Ziggo subscribers in swarms, before and after

In other words, despite the court order the number of BitTorrent pirates at the two censored Internet providers remains constant.

“Ziggo and XS4ALL subscribers who use BitTorrent apparently found different routes other than ‘The Pirate Bay’ to share files, and remain active as seeders to upload files to others,” the researchers note.

The results are not really unexpected, as there are countless other ways to download the torrents that are available on The Pirate Bay. Reverse proxies are one example, or indeed the many other BitTorrent sites that are out there.

The results will prove interesting in respect of a new lawsuit filed by BREIN against two other Dutch Internet providers. Now that it’s clear that a blockade has little effect, the anti-piracy group will have to present new arguments to warrant a Pirate Bay block.