Gurbaksh Chahal, Founder of RadiumOne

Serial entrepreneur Gurbaksh Chahal sold his first online advertising startup ClickAgents at 18 for $40 million. His second company BlueLithium was purchased by Yahoo Inc., for $300 million. His latest venture is RadiumOne, a fast-growing ad network that leverages social data on the Web. Chahal also published a memoir, The Dream (Palgrave Macmillan, 2008).