Marissa Mayer, vice-president, search products and user experience for Google Inc, unveils "Google Instant" during a news conference in San Francisco, California in this September 8, 2010, file photo. [Photo/Agencies]

SAN FRANCISCO - Yahoo on Monday announced that it has appointed Marissa Mayer, a former Google executive, to be its president and chief executive officer (CEO).

Mayer will also join Yahoo's board of directors and the appointment will be effective July 17, Yahoo said.

The appointment of Mayer signals a renewed focus on product innovation to drive user experience and advertising revenue at Yahoo, the company noted in a press release.

Mayer, the first female engineer hired at Google, joined the Internet search giant in 1999 as its 20th employee and led efforts for many of Google's most recognizable products including the search product and homepage.

She most recently served as Google's vice president of location and local services.

In a statement, Mayer said she was "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," she said.