Now three days into running Yahoo (Nasdaq: YHOO), the No. 3 search engine, CEO Marissa Mayer has already telegraphed that change is coming. She appointed the first editors for Yahoo News and Yahoo Finance, two of the company's most popular portals.

That's probably only the beginning of whatever turnaround Mayer plans for the Sunnyvale, Calif., search and media company. But it surely reflects the desires of Yahoo's biggest outside shareholder, Third Point Capital, which holds three seats on the board.

Last year, after the ouster of CEO Carol Bartz, Third Point Capital's managing partner, Daniel Loeb, announced his New York-based hedge fund had acquired stake in the company, which he charged has mismanaged its properties and was undervalued.

In a series of letters to former chairman Roy Bostock, Loeb wrote that popular sites like Yahoo News, Yahoo Finance and Yahoo Sports had been mismanaged and enjoyed great value, especially because they received more than 700 million monthly views.

So by naming Hillary Frey, a former journalist for Adweek who'd been with Yahoo News a year as editor-in-chief, and Aaron Trask, an alumnus of TheStreet, Inc. (Nasdaq: TST) as editor-in-chief of Yahoo Finance, Mayer's made a start.

Yahoo already has a close web partnership with Walt Disney Co.'s (NYSE: DIS) ABC News division and recently announced a new deal for financial news with Comcast's (Nasdaq: CMCSA) CNBC.

In May, Nielsen estimated Yahoo and ABC News was the most popular U.S. news website, with 62.1 milion views; Time Warner's (NYSE: TWX) CNN was No. 2, with only 39.6 million.

This month, Yahoo settled a patent lawsuit against Facebook (Nasdaq: FB), the No. 1 social networking site, with the two agreeing on cross-licensing as well as sharing advertising revenue.

Considering that Facebook's membership has risen above the 901 million mark reported on March 31, that could be another new market, especially now that Google News has been able to tap Google +, which last reported 190 million members.

Loeb, in his letters to management, argued that Yahoo hadn't moved aggressively enough to take advantage of the sites' popularity and branding. But it's clear Mayer, 37, got the message.

Loeb and two allies have been Yahoo directors since the ouster of CEO Scott Thompson in May. As owners of 5.8 percent of the shares, second only to the 5.9 percent stake owned by company co-founder David Filo, Loeb is moving quickly.

Reports said the Loeb group was instrumental in not offering the CEO job to interim boss Ross Levinsohn, who attended the Yahoo annual meeting last week and deflected questions concerning his tenure.

Mayer, of course, spent the past 13 years at neighboring Google (Nasdaq: GOOG), the No. 1 search engine, where she had the opportunity to monitor every Yahoo move. Most recently, she ran the Mountain View, Calif.'s moves to create email and maps, features Yahoo pioneered.

Most likely, some new steps will include finally hammering out deals with Yahoo's international partners, Yahoo Japan (Tokyo: 4689) and China's Alibaba Group, so that Yahoo can recoup some of its investments while retaining shares in popular Asian sites. Goldman Sachs (NYSE: GS) and Allen & Co., have been working on this project for months.

Another goal might be acquiring companies with strategic assets and inroads into new fields. Yahoo reported cash and investments exceeding $2.4 billion in the second quarter. While a far cry from the $49.3 billion Google reported last quarter, Mayer could use it for some smart shopping.

Yahoo certainly can't go elephant hunting, said Rick Summer, analyst with Morningstar. Nor could it likely copy the strategy of AOL (NYSE: AOL), where turnaround CEO Rick Armstrong made some high-profiled acquisitions such as the $310 million takeover of The Huffington Post.

Indeed, AOL just beat back activist shareholder Starboard Value Management at its June annual meeting. The dissident shareholders argued AOL, too, was mismanaged and undervalued.

What might Mayer look for? Besides whatever companies she'd been eyeing at Google until Monday, some could include startups seen at industry trade shows and financial forums, which could enhance the functions and features.

One analyst suggested Whale Wisdom, a provider of investor filing information to the Securities and Exchange Commission for hedge funds, as a target that could broaden Yahoo Finance.

Another could be Baydin, a marketer of email management tools like Boomerang for Gmail, which could be an add-on to Yahoo Mail. Among the young, especially, the Yahoo address is almost as uncool as AOL, said Joseph Pastore, Jr., a professor at Pace University's Lubin School of Management.

Yahoo shares rose a nickel to $15.75 in late Thursday trading, boosting their gain since Mayer's appointment Monday to 7.2 percent. Since Third Point acquired its Yahoo stake, the shares have gained 22 percent.