On any given day, video-sharing site YouTube hosts millions of video clips posted by independent Web users around the world. While most of the clips are home videos and film shorts made by would-be TV stars, some footage is stolen from media firms in direct violation of copyright laws.

Given past violations by peer-to-peer media-sharing sites, it was only a matter of time before media companies would jump Google's case over illegally posted content and seek financial reparations. Viacom, a regular victim of illegal video sharing on YouTube, is suing Google for $1 billion in damages over copyright violations at the paid-search leader's online video division. Viacom's court filing claims that YouTube has been screening shows from its MTV and Nickelodeon networks illegally, and that about 160,000 clips of its programs have been loaded on YouTube's site and viewed more than 1.5 billion times.

The legal scuffle parallels past suits between the Recording Industry Association of America and online media-sharing sites like Napster and Grokster. The courts found those sites liable for copyright infringements related to members' online music sharing. Napster shut down after being bankrupted by multimillion-dollar settlements with copyright owners; Grokster went offline after the U.S. Supreme Court ruled it could be held liable for copyright infringements committed by its users.

But some groups say that the YouTube situation is not the same as the problems faced by past peer-to-peer file sharing services. Google has sided with such opinions, claiming that it hasn't violated the laws.

Despite the high stakes and heated opinions on both sides, many observers believe that there is more bark than bite in Viacom's lawsuit. Additionally, Google's deep pockets appear to contain the cash necessary to stave off threats to YouTube's existence. Google made headlines in 2006 when it acquired the top video-sharing site for $1.65 billion in stock. At least for now, YouTube remains among the highest trafficked sites on the Web.