A U.S. District Court decision after a three-year battle could be a landmark ruling for future Internet copyright issues and restrict the culpability of website providers for the copyrighted material posted by users.

The court ruled Google Inc.’s YouTube video-sharing website didn’t infringe on copyrights owned by movie and television producer Viacom Inc. and wasn’t liable for infringement. TV shows are often posted by users on the site and are not reviewed by YouTube before they appear to the wider Internet community.

“The provider must know of the particular case before he can control it,” said Judge Louis Stanton in the ruling. “The provider need not monitor or seek out facts indicating such activity.”

But once infringing content is detected and YouTube is notified, the site will be required to remove the material, according the ruling. That, however, is a practice YouTube already engages in.

In it’s arguments before the court, YouTube cited the safe-harbor provision of the Digital Millennium Copyright Act, which states that a service provider isn’t liable for infringement if it removes material from its site when notified by the copyright owner.

Viacom argued that Google, which bought YouTube for $1.65 billion in 2006, knew that the site was a hotbed for copyright infringement. Viacom was seeking $1 billion in the lawsuit and was hoping Google would be ordered to review all content before it is posted.

“The decision follows established judicial consensus that online services like YouTube are protected when they work cooperatively with copyright holders to help them manage their rights online,” said Kent Walker, Google vice president and general counsel, in Google’s official blog.

Viacom has said that it plans to appeal the ruling, Bloomberg reported.