Google will soon be allowing advertisers to have more options. These include targeting users by site, a new max CPM bidding option, and additional ad formats including animated image ads. Details of the enhancements are here.
In addition to the standard keyword-targeted ads, advertisers will be able to place ads on specific sites in the Google content network and these ads will not appear on the search network. With site-targeted advertising, advertisers will set a maximum CPM, which is the maximum price they're willing to pay for every thousand impressions their ad receives on a particular site. Their ads compete for advertising space on the site with other site-targeted ads as well as with keyword-targeted ads. Advertisers will pay no more than the minimum price needed to run an ad on the site. In many cases, they will pay a price lower than their max CPM.
I am not sure how this will affect publishers running Adsense, if at all.