IsoHunt, a popular website offering BitTorrents of mostly pirated material, is to shut down following a court settlement.
The site's owner, Canadian Gary Fung, has agreed to pay $110m (£68m) to the Motion Picture Association of America (MPAA).
MPAA chairman Chris Dodd said the move was a "major step forward" for legitimate commerce online.
In a blog post, Mr Fung said: "It's sad to see my baby go."
The site is currently still online, but will soon be shut. It is one of the most popular sites of its kind on the internet.
A group of companies, including Disney, Paramount and Twentieth Century Fox, accused the site of wilfully infringing copyright by listing millions of popular movies and TV programmes - in a court battle that has lasted for more than seven years.
Now Mr Fung has agreed to settle. He added: "I have fought the good fight, I have finished the race and I have remained faithful. 10.5 years of IsoHunt has been a long journey by any business definition and forever in internet start-up time.
"It started as a programming hobby in my university days that has become so, so much more."
Court documents acknowledged that it is unlikely that Mr Fung's company could pay $110m, and that the MPAA would probably receive between $2m and $4m.
Degree of separation
Like a similar site, The Pirate Bay, that has been blocked in the UK by a court order, IsoHunt did not host pirated material itself.
It instead acted as a directory of sources from which to download illegal files. According to court documents, Mr Fung's defence hinged on this degree of separation - and argued that it was the users of IsoHunt responsible for distributing pirated material, not IsoHunt.
The Californian court disagreed.
"It sends a strong message that those who build businesses around encouraging, enabling, and helping others to commit copyright infringement are themselves infringers, and will be held accountable for their illegal actions," said MPAA chairman Mr Dodd.
"The successful outcome of this landmark lawsuit will also will help preserve jobs and protect the tens of thousands of businesses in the creative industries, whose hard work and investments are exploited by sites like IsoHunt."
'Reluctant revolutionary'
Ahead of the ruling, Mr Fung had taken to social news site Reddit to take part in an AMAA - Ask Me Almost Anything - session.
In it, he described himself as a "reluctant revolutionary", and backed calls for copyright reform.