The Yahoo board has appointed Dr. Raymie Stata as the top technology executive at the company, promoting him to Chief Technology Officer (CTO), from his previous position as Chief Architect at the company.

Prior to joining Yahoo, Dr. Raymie Stata founded Stata Laboratories, a firm that developed a web-based email client along with advanced anti-spam filter technologies, that was acquired by Yahoo in 2004. He has worked at the company since the acquisition.

The new position is effective immediately.

Mr. Ari Balogh was the preceding CTO at Yahoo after he announced he would resign as CTO for personal reasons. His resignation went into effect today. He was with Yahoo since the summer of 2008.

A number of other external people were reportedly considered to replace Balogh as CTO, including a former Microsoft Corp. Internet executive.

A number of top-level changes have taken place over the last year or so at Yahoo, including the resignation of co-founder Jerry Yang at his position at the company as chief executive.

Jerry Yang resigned in November 2008 following mounting pressure after he failed to maximize shareholder value after he rejected an unsolicited takeover bid by chief rival Microsoft Corp. for a significant premium over the firms stock price.