Marissa Mayer: Newest Top Female Executive

Facebook COO Sheryl Sandberg at a 2011 gala in New York. Sandberg, a Google veteran, has been a steadying influence at Facebook, which did not have concrete plans for become profitable before she was hired in 2008 by founder Mark Zuckerberg. In 2012 she became the first woman on Facebook's board. (Shahar Azran/Getty Images)