It's been a tough year for a company that was once a shining Internet pioneer but has struggled financially and fallen behind other Internet companies, including , and .

Stepping in to take over Yahoo will be a challenge for Mayer.

"I am honored and delighted to lead Yahoo, one of the Internet's premier destinations for more than 700 million users," Mayer said in a statement from Yahoo. "I look forward to working with the company's dedicated employees to bring innovative products, content, and personalized experiences to users and advertisers all around the world."

Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at , on or subscribe to . Her email address is .

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