Facebook CEO Mark Zuckerberg has answered questions from US lawmakers for a second day. The first hearing didn't turn out to be the grilling some had expected and the company's stock registered its best day in more than two years. So how did Zuckerberg come out on top from his trip to Washington? Mobin Nasir takes a look. We also speak to David Madden, an analyst at CMC Markets in London, and Max Wolff Chief Economist at Phoenix Group, in New York.