Yahoo’s line of thinking with regards to the big Microsoft/Yahoo search and advertising deal is that it will benefit both Microsoft and Yahoo’s advertisers, as well as consumers and publishers. It will benefit advertisers because it will increase search volume, with results from both Bing and Yahoo being taken into consideration.
http://www.webpronews.com/topnews/2010/03/09/yahoo-on-microsoft-deal-benefits-for-advertisers-consumers-publishers