Marc Benioff is the founder and CEO of Salesforce. He lives in SF. His twitter is @benioff.

Benioff is a big proponent of philanthropy and a public proponent of having the Bay Area tech industry do more to give back to the community. He and his wife have made two donations of $100mn each to UCSF, along with donations to many other causes. And Benioff publicly urges other tech companies to give more (with mixed results).

News, etc.