The Motion Picture Association (MPA) has won an injunction to stop a UK-based website helping net users to illegally download films.
High court judge Mr Justice Kitchin ruled that Newzbin uses a "sophisticated technical" system to allow web users to illegally file-share films and infringe copyrights.
Newzbin employed Usenet - an early internet communication system that helps members download large numbers of films in one go.
Kitchin said Newzbin was "focused on piracy in that it locates and categorises unlawful copies of films and displays the titles of these copies in its indices".
"Newzbin is a source of immense damage to the creative sector in the UK and worldwide," said Ted Shapiro, from the European arm of the MPA.
"This is an important decision and it sends a clear message that websites focusing on providing viewers with pirated film and TV programmes infringe copyright and are liable for their actions - even where those websites don't themselves host the content."
Newzbin defended itself, saying it was simply a search engine and was not responsible if web users illegally downloaded content found using Newzbin.