Now that Google's (NASDAQ: GOOG) YouTube has set up a system to broadly market video advertising across its website, Wall Street analysts and the media have begun to engage in a debate about how much revenue the project will bring in. The spread of estimates is so wide that it opens the question of whether anyone can put up a fair estimate of the potential YouTube contribution.

Piper Jaffray analyst Gene Munster, who is known for being extremely bullish on many internet stocks, has a high-end revenue estimate for Google of $1.1 billion over the next year, according to TheStreet.com. That assumes an extremely high $40 cost per thousand pages sold and very wide acceptance of the video ad format that YouTube is offering. That would also mean that the project could be as much as 10% of Google's revenue, which would be an extraordinary benefit to shareholders.

UBS analyst Ben Schacter has come up with a much more modest contribution figure of $120 million for YouTube video ad revenue in 2008. The number assume very modest adoption of the YouTube video ad product. It would also mean that YouTube would not make a meaningful contribution to Google's revenue at all.

Hanging over all of this the the Viacom (NYSE: VIA) copyright-infringement lawsuit that is seeking $1 billion from Google for allowing the entertainment company's content to be posted at the video sharing site. It won't matter if the YouTube video ads bring in a billion dollars if it has to go right back out the door.

Douglas A. McIntyre is a partner at 24/7 Wall St.