This is a battle that's just beginning. I can see this being the big Internet story in a couple of years. Users, for the most part, do not like banner ads. Users do not click on banner ads in large enough numbers so that advertisers are satisfied. Advertisers become more and more aggressive, forcing users to look at the ads.
Users still resist.
The advertisers continue to become more and more aggressive until a critical mass is reached. There really isn't much more aggression to be implemented. I fear that advertisers will start to see banner ads as not effective and start to put their ad money in more traditional media. That means lower ad revenue for the sites that would run supported solely by advertisers. The costs for running the sites won't go away anytime soon, so the money has to come from somewhere.