It's not yet clear if anyone who uploads videos to YouTube can choose to have ads and to split revenue with Google, but one thing is sure: the format of the ads. "We're looking at executions like a very quick little intro preceding a video, then the video, then a commercial execution on the backside of the content", said YouTube's Suzie Reider.
While many people will say that those who visit YouTube don't like ads and they'll move to other video sites, Google's main priority is to create a model that works well for advertisers, but doesn't disrupt the user experience.