What's in it for advertising networks?
They get "Google's extensive network of blogs, forums and websites."
Opening up a potential new revenue stream for thousands of site operators worldwide, the move underlines the search giant's determination to extend its reach beyond text advertising and into the world of display.

Source: http://www.utalkmarketing.com//Pages...rticleID=15116
This is an interesting article about possible changes that could occur in advertising due to Google's meld of Adsense with traditional online advertising.