Facebook CEO Mark Zuckerberg speaks at an event at Facebook's Headquarters office in Menlo Park, California on January 15, 2012. Facebook launched a search engine Tuesday for shared content as a way ... more 

Facebook CEO Mark Zuckerberg speaks at an event at Facebook's Headquarters office in Menlo Park, California on January 15, 2012. Facebook launched a search engine Tuesday for shared content as a way to find out more about friends on the huge social network in a potential challenge to Google and other Internet firms less