Mark Zuckerberg wants you to know that he's not running for president. In recent months, Facebook's CEO has dined with a family at their home in Ohio and been photographed working on an assembly line at a Ford factory, meeting with members of the military, and even feeding a calf. But as much as such outings may look and sound like someone raising his profile for a political run, Zuckerberg insists that's not the case. "Some of you have asked if this challenge means I'm running for public office," Zuckerberg recently wrote in a Facebook post. "I'm not." And that...