Salesforce.com founder Marc Benioff and his wife Lynne tied with Zuckerberg for No. 10 on the overall top 50 list.
In June, the Benioffs announced a major donation to a new children's hospital at the University of California at San Francisco -- Marc's hometown. The $100 million gift is meant to make SF a global center for children's care, Marc said, and spur others to give generously.
It's hardly Benioff's first brush with philanthropy. In 1999, he founded the Salesforce Foundation to give products, money and employee volunteer hours to charity. His books The Business of Changing the World and Compassionate Capitalism encourage CEOs to build "strategic corporate philanthropy" straight into their business model.