Mark Zuckerberg, chief executive officer of Facebook Inc., speaks during the Facebook F8 Developers Conference in San Francisco, California, U.S., on Wednesday, March 25, 2015. Facebook Inc. is opening up its Messenger chat application, letting developers create software for people to add photos, videos and other enhancements to their online conversations. Photographer: David Paul Morris/Bloomberg via Getty Images

Mark Zuckerberg, chief executive officer of Facebook Inc., speaks during the Facebook F8 Developers Conference in San Francisco, California, U.S., on Wednesday, March 25, 2015. Facebook Inc. is opening up its Messenger chat application, letting developers create software for people to add photos, videos and other enhancements to their online conversations. Photographer: David Paul Morris/Bloomberg via Getty Images