It seemed like a crazy when a little over years ago Facebook announced it was purchasing WhatsApp for $19 billion. But the reason Facebook was wiling to pony up such an obscene sum is partly because of how wildly popular WhatsApp was at the time. It’s only grown since then, and according to its developers WhatsApp users make over 100 million

Source: Hot Hardware – WhatsApp Users Make A Collective 100 Million Voice Calls Every Day