-By Brian Morrissey

NEW YORK Yahoo! is shaking up its ad sales leadership again, replacing sales chief David Karnstedt with former Microsoft exec Joanne Bradford. Her mandate includes running all ad sales, as well as Yahoo!'s small business services and HotJobs.

Adam Grossberg, a Yahoo! rep, denied that Bradford is replacing Karnstedt, who decided to leave the company earlier this summer. While Bradford will assume Karnstedt's responsibilities overseeing U.S. sales, her role as svp of U.S. revenue and market development will be broader than Karnstedt's, he said.

Karnstedt will depart Yahoo! on Sept. 16 to become an entrepreneur in residence at Redpoint Ventures, a Silicon Valley venture capital firm, the company said.

Bradford will report to Hillary Schneider, executive vice president of Yahoo!'s U.S. operations.
 
She joins after a brief stop at Spot Runner, the Internet-based TV ad platform. Bradford joined the startup in March to lead its national advertising services.
 
In Bradford, Yahoo! is bringing on a well-known Internet executive. She worked in senior positions at Microsoft for more than seven years, and in her last position at the company ran all of MSN. Prior to that, Bradford was chief media revenue officer for Microsoft Digital Advertising Solutions. She is credited with convincing top Microsoft executives to embrace advertising as an important part of the company's future. Prior to Microsoft, Bradford held posts at BusinessWeek.
 
She is known as a strong proponent of brand advertising online, much like former Yahoo! sales chief Wenda Harris Millard. Karnstedt replaced Millard in June 2007 in a move interpreted as Yahoo!'s embrace of search and direct response advertising, as Karnstedt had led search ad operations at the company.
 
"Joanne's deep understanding of the marketplace coupled with her proven ability to package and deliver results-driven solutions for the world's biggest brands will help Yahoo!'s customers connect with the audiences they most want to reach not just on Yahoo!, but across the Web," Schneider said in a statement.