Facebook has announced an agreement to buy WhatsApp, the mobile messaging platform used by over 450 million people. The deal involves $4 billion in cash and an additional $12 billion in Facebook stock. They say WhatsApp will remain independent; its headquarters won't move, and it will continue to exist separately from Facebook's Messenger app. Mark Zuckerberg indicated they will focus on growth: 'Over the next few years, we're going to work hard to help WhatsApp grow and connect the whole world. We also expect that WhatsApp will add to our efforts for Internet.org, our partnership to make basic internet services affordable for everyone.' On WhatsApp's blog, they say, "Here’s what will change for you, our users: nothing. WhatsApp will remain autonomous and operate independently."