This photo of Mark Zuckerberg, creator and CEO of Facebook, was taken at a press conference in 2011 during the G-8 summit in Deauville, France. Born in 1984, Zuckerberg turned 27 that year. Facebook went public the next year, making Zuckerberg officially a multi-billionaire.
(Mark Zuckerberg photo by Guillaume Paumier via Wikimedia Commons, published under a Creative Commons 3.0 license. Thanks, Mr. Paumier!)