In a surprise move, Yahoo! today announced that it has found a new CEO in Marissa Mayer, the Google vice president who heads the company's Maps and location services.

Mayer, who joined Google as its first female engineer and 20th employee overall, will become Yahoo!'s fourth permanent or interim CEO in the past four years. The company fired its most recent chief executive, Scott Thompson, after a scandal broke in May regarding a falsely claimed computer science degree on his resume.

At just 37, Mayer had become a public face of Google despite never having occupied one of its senior executive positions. She spoke frequently at conferences and was the subject of multiple flattering magazine profiles on women in business. Last year, she conducted a high-profile hour-long interview with Lady Gaga.

In an interview with The New York Times, Mayer said she was first approached about the CEO job at Yahoo! in June. Her selection, however, was widely unexpected by outsiders, as most analysts believed interim CEO Ross Levinsohn had an inside track to the permanent position.

Despite Yahoo!'s recent troubles and stiff competition from Facebook and Google, Mayer called her new employer “one of the best brands on the Internet ” and said she was confident she could leverage the company's core remaining strengths: finance, sports and email. Overall, moving to the executive chair was "a reasonably easy decision," she said.

Mayer joins a short list of women who have reached the top levels of power in Silicon Valley, including her friend and influential Facebook COO Sheryl Sandberg and Hewlett-Packard CEO Meg Whitman. Here she is on Charlie Rose in 2009 talking about the way Google makes new products.

[via NYT]