Mark Zuckerberg walks to morning sessions with his girlfriend, Priscilla Chan, during the Allen and Co. Sun Valley Conference in Sun Valley, Idaho, in July 2011. (Julie Jacobson / Associated Press)
Facebook founder Mark Zuckerberg through the years
Mark Zuckerberg, right, talks with Facebook employees before announcing the social network’s new location-based service called Places during a Palo Alto news conference in August 2010. (Tony Avelar / Associated Press)
