The case is significant for adult webmasters because it clears the murky legal waters for actionable cases in Europe, which is bound by the 2000 European E-Commerce Directive.
Article 14 of the E-Commerce Directive only requires an ISP to divulge personal details if an illegal act has been committed, such as in the case of child pornography.
The E-Commerce Directive, which serves a tool for European governments to set online taxes, deals with content liability, for the most part.
But now it appears that the door could open for industries ready to take on peer-to-peer file swappers
In most cases the record industry knows the IP address but can only match these to personal details with the assistance of the ISPs.
In the recent case, the Appeals Court of Amsterdam upheld a decision by a lower court which required Lycos to make available data from one of its websites to a third party on the grounds that the information constituted an apparently unlawful act.
The case was brought by Netherlands attorney and stamp trader Augustinus Bernard Maria Pessers who claimed that a Lycos subscriber had unlawfully accusing him of fraud.
The Lycos subscriber published Pessers name on his website and provided an email address instructing others to report any other fraudulent incidents Pessers might have committed.
Lycos shut down the website after a request from Pessers, but declined to reveal the identity of the subscriber, prompting Pessers to file suit against the ISP.
The appellate court ruled in late June it would be against the common interest if Pessers did not have the chance to confront Lycos, which hosted the website.
The case is Lycos Netherlands vs. Pessers, No. 1689/03KG.