Viacom accused Google Inc of turning a blind eye to illegal video clips on its YouTube site in a bid to attract viewers, according to court documents released on Thursday.
Google countered that Viacom managers continued to secretly upload content to YouTube even after the media company had filed the $1 billion copyright suit in March 2007.
Viacom, which owns cable networks MTV and Comedy Central among others, charged that Google and YouTube executives were aware videos were being illegally uploaded to the site, failed to stop it, and, in some cases, broke the law by adding copyrighted clips themselves.
"YouTube was intentionally built on infringement and there are countless internal YouTube communications demonstrating that YouTube's founders and its employees intended to profit from that infringement," Viacom said in a statement on Thursday, as the documents were released.
As part of its evidence, Viacom provided excerpts from emails in 2005 between YouTube co-founders Chad Hurley, Steve Chen and Jawed Karim. YouTube is a division of Google.
In a July 19, 2005 email, for instance, Chen wrote to Karim and copied in Hurley: "We're going to have a tough time defending the fact that we're not liable for the copyrighted material on the site because we didn't put it up when one of the co-founders is blatantly stealing content from other sites and trying to get everyone to see it."
YouTube Chief Counsel Zahavah Levine, on a blog post, said Viacom's brief "misconstrues isolated lines from a handful of emails."
The opening briefs in the Viacom vs YouTube lawsuit are widely seen as a test of the Digital Millennium Copyright Act (DMCA) which YouTube believes protects it from Viacom's claims.
The law criminalizes the production of technology to circumvent anti-piracy measures while limiting the liability of providers of online services for copyright infringement by their users.
While it is still early in the legal battle, it appeared Google was trying to cast Viacom's strategy as hypocritical by claiming several of the company's own managers and agencies had continued to upload videos to YouTube.
"Viacom routinely left up clips from shows that had been uploaded to YouTube by ordinary users," said Levine in the blog post.
"Executives as high up as the president of Comedy Central and the head of MTV Networks felt 'very strongly' that clips from shows like The Daily Show and The Colbert Report should remain on YouTube," Levine said.
With YouTube being easily the most popular online video site, many TV producers upload clips of their shows for promotional purposes.
YouTube said this week its users upload up to 24 hours of video every minute.
Google also claimed Viacom had in 2006 expressed interest in buying YouTube, which the Web search leader subsequently bought months later for $1.65 billion.