Sheryl Sandberg, 48, chief operating officer (COO) of Facebook and founder of Leanin.org (also known as the Lean In Foundation). In June 2012, she was elected to the board of directors by the existing board members, becoming the first woman to serve on Facebook's board. Before she joined Facebook as its COO, Sandberg was vice president of global online sales and operations at Google, and was involved in launching Google's philanthropic arm Google.org. Before Google, Sandberg served as chief of staff for United States Secretary of the TreasuryLawrence Summers. She was named in the Time 100, an annual list of the 100 most influential people in the world according to Time magazine. As of June 2015, Sandberg is reported to be worth over $1 billion, due to her stock holdings in Facebook and other companies. (AP Photo)