Jonathan Greenblatt is a serial social entrepreneur with a string of successes. He has helped to build several brands, including Ethos Water, which was bought by Starbucks in 2005. He also worked with Google and was, until last month, the director of the Office of Social Innovation and Civic Participation at the White House. From July 1 he became the national director of the Anti-Defamation League. Greenblatt was named a senior fellow at the Wharton School in December 2014. Throughout his career, Greenblatt has helped to evolve what the idea of social entrepreneurship means. In a recent interview with  Katherine Klein , vice dean of Wharton’s Social Impact Initiative , Greenblatt talked about the business of social impact: Where it has been, where it is headed, and how we can tell if a company is doing the good it aspires to do. An edited transcript appears below. Katherine Klein : What is a social entrepreneur?…