Today it was announced that Facebook is buying WhatsApp for a whopping $16 billion. The SEC filing today reveals that WhatsApp will continue to operate as an independent entity under Facebook (much as Instagram did after their acquisition by Facebook), though the company claims that the deal will accelerate "Facebook's ability to bring connectivity and utility to the world." Facebook has long had their own messaging service in Facebook Messenger and it's not exactly clear how WhatsApp will complement that going forward.
Facebook is the world's largest social network with 1.23 billion users and growing, and CEO Mark Zuckerberg said that "WhatsApp is on the a path to connect 1 billion people. The service that reach that milestone are all incredibly valuable."