Monetization strategy is what's stopping Whatsapp. Eventually, there will be an official API so business can hook CRMs to clients' Whatsapp accounts. However, FB is first trying that with Messenger API/bots. I assume Whatsapp API/bots comes next.
FB did not pay billions for the most popular chat app just to let 1 billion people use it for free forever...
Free? Every WhatsApp user paid Facebook on day one with the contents of their address book and how frequently one person contacts another. This is of huge value if your business model is exactly to gather this kind of data.
All the talk about encryption and privacy seems to ignore this basic point. Association can be dangerous and this does not protect people from exposing themselves in that way.
FB did not pay billions for the most popular chat app just to let 1 billion people use it for free forever...