[Advanced] Yahoo! Gets a New CEO (2)

As an early Google employee, Mayer was also something of a celebrity in Silicon Valley.

Still, the move to Yahoo is an opportunity for Mayer to claim a bigger stage.

Questions remain whether Mayer can make a difference at Yahoo. Some openly wonder if Mayer's appointment will make a dent. And whether Yahoo might besmirch her stellar reputation if things don't work out.

"She's not at Google anymore, and if she's going to try and out-Google Google, that would be a terrible mistake," analyst Yarmis says. "Clearly, she saw that her path to the top at Google wasn't going well, and revenge can be a powerful, and dangerous, motive."

Mayer's appointment brings a person with cachet and connections to Yahoo, analysts say. But Yahoo has defined itself as a media company working to attract advertising dollars, an agenda echoed by former interim CEO Levinsohn. Mayer's Google tenure and engineering background could signal an about-face for Yahoo.

"She's an engineering type, which in some ways is good news. Ross Levinsohn had said they would focus as a media company, and that was not necessarily good news," says IDC analyst Karsten Weide.

Yahoo's advertising sales business needs to change to shore up its shortcomings, he says.

The situation isn't entirely dire. The portal attracts about 700 million visitors a month, which helped it generate nearly $1 billion in ad sales last quarter.

But that business is under siege from Google, Facebook and an armada of start-ups vying for eyeballs and revenue. Yahoo's slice of the nearly $40 billion U.S. online ad market — 16% in 2009 — was 9.5% in 2011 and could slide to 7.4% this year, according to eMarketer.

Whether the new CEO and a new board are the fix remains an open question.

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