The transition of all of Yahoo's advertising serving to Microsoft is being set for next Monday, October 11th, according to an email being sent to Yahoo's advertisers. According to Yahoo, the firm is set to begin moving its ad serving platform from the Yahoo! Search Marketing platform to Microsoft Advertising adCenter, beginning as early as next Monday. Yahoo had previously only said the move would take place sometime in the fall. Yahoo said that it expects that by the end of October, its users will have a single account to advertise on Bing, Yahoo! Search, and other sites. Yahoo shifted its search services in August entirely to Bing's back end, and has been in process of moving its ad system to adCenter.