Sam Altman is president of Y Combinator and was the co-founder of Loopt, a location-based social networking app, which was part of YC's first batch of startups in 2005 and later acquired by Green Dot in 2012. Prior to taking over as Y Combinator's president, Sam was a part-time partner at Y Combinator. As an early innovator in mobile location services, Sam joined Apple CEO Steve Jobs on stage at WWDC 2008, presenting Loopt as one of the first applications in the iPhone App Store.