Despite improving click through rates (which they will definitely achieve by reducing the number of ads on the page), it will not lead to improving revenues. CPMs are being depressed by competition, not just oversupply. Click rates are a function of users' hatred of banner ads and conditioning to ignore the top and right of the web page. And even with better targeting, which commands premium CPMs, the total buys are smaller. All of these lead to continuously declining advertising revenues from display ads, whether or not they are able to improve click rates from nearly zero to something slightly higher.
U.S. Internet users saw 4.5 trillion banners last year, according to ComScore. That's 2,000 per user a month, 24,000 for the year.
informal survey of twitter followers about recall and clicks on banners by @bmorrissey
