Facebook has announced the acquisition of WhatsApp, the famous instant messaging application for mobile devices. The price that Mark Zuckerberg’s social network will pay is $16 billion of which $4 billion in cash and $12 billion in Facebook shares. An additional $3 billion in restricted Facebook shares will be paid as a bonus tied to WhatsApp’s founders and employees that will vest over four years subsequent to closing. WhatsApp Inc. CEO Jan Koum will enter Facebook’s board of directors.