Yahoo Inc. (YHOO) on Monday named Marissa Mayer, a longtime Google Inc. (GOOG) executive, to be its next chief executive officer, as the onetime Internet pioneer tries to reverse its downward course. In a statement, Ms. Mayer said: "I am honored and delighted to lead Yahoo, one of the Internet's premier destinations for more than 700 million users. 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." Yahoo was being run by interim CEO Ross Levinsohn after the exit earlier this year of then-CEO Scott Thompson over some misstated credentials. Yahoo has gone through a revolving door of CEOs in recent years.