Samuel H. "Sam" Altman is an entrepreneur, programmer, venture capitalist and blogger. He is the president of Y Combinator. He was previously a co-founder and CEO of Loopt, a location-based social networking mobile application, which was acquired by Green Dot Corporation in 2012. Altman was named one of the "Best Young Entrepreneurs in Technology" by BusinessWeek in 2008 and was listed as one of the five most interesting startup founders between 1979 and 2009 by Paul Graham. Altman studied computer science at Stanford University. He also taught a class there in the Fall of 2014.