It amazes me that Overture let Google grab PPC...

http://www.reuters.com/newsArticle.jhtml?type=internetNews&storyID=6547221

Google has better pricing feedback in their system (the clickthrough rate), broader distribution, and is more automated (and thus cheaper to run). they can cut better deals and even do stuff at slim margins to where Overture can't really compete...and thus they steal accounts from them.

Google has better pricing feedback in their system (the clickthrough rate), broader distribution, and is more automated (and thus cheaper to run). they can cut better deals and even do stuff at slim margins to where Overture can't really compete...and thus they steal accounts from them.
So inevitablity pushes Overture into a shrinking position.