YouTube, which serves as a repository for user-contributed video clips, was acquired by Google last fall. Since then, Google has been trying to shore up deals with major entertainment companies in order to fend off such a lawsuit, and has recently inked agreements with CBS, Warner Music Group and Sony BMG Music Entertainment.

But whatever Google offered Viacom apparently wasn’t enough. Last month Viacom ordered Google to yank more than 100,000 clips belonging to the entertainment giant, including material culled from Comedy Central and MTV. However, as of March 14th, clips of Comedy Central’s “The Daily Show” and “The Colbert Report” were still a part of YouTube’s video stash.

Since the original notification, Viacom claims that it has identified more than 50,000 additional videos belonging to the company.

YouTube, which allows users to post video, no matter if it’s homemade or the latest episode of “24,” has long maintained that it is only a service provider, and that it is exempt from most online copyright laws. Under the Digital Millennium Copyright Act, service providers cannot be sued for users’ infringing activity. That is, as long as the providers remove the copyrighted material upon notification.

“We’re saying that the DMCA protects what we’re doing,” said Alexander Macgillivray, Google’s associate general counsel for products and intellectual property. “The DMCA is silent on what we have to do if we don’t get a notice.”

However, the DMCA became law back in 1998, when service providers were essentially Web hosting companies. The legal opinion at that time was the companies couldn’t be expected to act as copyright cops. Of course, that was before three ex-PayPal employees came up with the idea to create a site that would eventually host more than 100 million clips and receive more than 20 million visitors a month.

But removing copyrighted material from a Web site where users post more than 64,000 clips per day has to be a task of almost Herculean proportion. YouTube may have removed the specified vids last month, but users kept seeding the site with more MTV, more Spike, more TV Land and more of everything Viacom.

And Viacom isn’t mincing words in its lawsuit, saying YouTube “harnessed technology to willfully infringe copyrights on a huge scale,” and had “brazen disregard” for intellectual property laws.

“There is no question that YouTube and Google are continuing to take the fruit of our efforts without permission and destroying enormous value in the process,” Viacom said in a written statement. “This is value that rightfully belongs to the writers, directors and talent who created it and companies like Viacom that have invested to make possible this innovation and creativity.”