Facebook CEO Mark Zuckerberg listens to a question after introducing a new feature called "Graph Search" during a media event at Facebook headquarters in Menlo Park, California January 15, 2013. ... more 

Facebook CEO Mark Zuckerberg listens to a question after introducing a new feature called "Graph Search" during a media event at Facebook headquarters in Menlo Park, California January 15, 2013. REUTERS/Robert Galbraith less