Sheryl Sandberg is a leader. A woman and a leader. She serves as Facebook’s COO. She joined the firm in 2008, and today, she manages Facebook’s sales, marketing, business development, human resources, public policy and communications. It’s a massive job, but one well suited to Sandberg, who not only built and managed Google’s successful online sales and operations program but also served as an economist for the World Bank and Chief of Staff at the US Treasury Department. She earned a MBA from the Harvard Business School.