Yahoo shares haven't traded above $20 since September 2008. The announcement came after the market closed Monday. On Tuesday, it lost 3 cents to $15.62 in midday trading.
"If she can pull this off and turn around Yahoo, it will make her legacy," Gartner Inc. analyst Allen Weiner said of Mayer. "Yahoo's iconic yodel has been missing for a long time. Her mission will be to bring that yodel back."
This will be the first time that Mayer has run a company as she steps out of the long shadow cast by the Google's ruling triumvirate — co-founders Larry Page and Sergey Brin, along with Executive Chairman Eric Schmidt.
Although she had her responsibilities at Google narrowed two years ago, Mayer is still widely considered to among the Internet industry's brightest executives. A Wisconsin native, Mayer is a mathematics whiz with a sponge-like memory and a keen eye for design.
Mayer joined Google in 1999 as its 20th employee and went on to play an integral role in helping Page and Brin exploit their online search technology to outmaneuver Yahoo at a time when it was still the larger of the two companies. Now, it takes Google a little more than a month to generate as much revenue as Yahoo does in an entire year.
During Google's rise, Mayer helped oversee the development and design of the company's popular email, online mapping and news services. She also became a topic of Silicon Valley gossip during Google's early years while she dated Page for three years. They have since gotten married to other people.