Yahoo has appointed former Google executive Marissa Mayer as its CEO. She replaces Scott Thompson, the former PayPal president who left the Yahoo post after admitting to faking his CV, less than six months into his tenure.

Mayer, who will also be Yahoo's president and hold a seat on the board, will begin on Tuesday.

Most recently, Mayer was in charge of Google's Local, Maps and Location products.

She was for many years one of Google's most visible and well-known executives, joining as the search giant's 20th employee.

Thompson, who took over as CEO in January, left in May after it surfaced that he didn't have a computer science degree, contradicting his public professional biography.

Reports later emerged that his resignation was due instead to a cancer diagnosis.

Thompson was picked after Yahoo's board fired Carol Bartz, who became CEO in 2009 after an illustrious career that included many years as CEO of Autodesk.

Yahoo's board decided Bartz was unable to deliver the expected financial and technological rebirth of the embattled company.

Mayer will also have have her work cut out for her.

Yahoo has been struggling to jump-start its revenue and regain the technology edge that made it one of the Internet market leaders in the late 1990s and the first half of the 2000s.

Mayer will be expected to boost product development as a key to increasing usage and revenue, according to Yahoo.

"I look forward to working with [Yahoo's] dedicated employees to bring innovative products, content, and personalised experiences to users and advertisers all around the world," Mayer said in a statement.

Prior to her current role at Google, Mayer led Google's search services and other key products like iGoogle, Google News and Gmail. She started at Google in 1999.

Yahoo's CEO role was performed on an interim role by Ross Levinsohn, a Yahoo executive vice president and head of Global Media.