WhatsApp, unknown in some countries has a staggering propagation in the world, with 1 million of downloads per day, 450 million of members, 10 billion of messages exchanged every day.
This application works as Kik, ie it replaces the sms and mms. It is much more popular than Kik.
It was launched by two former guys of Yahoo.
It is free for the first year and cost then $ 0.99 per year.
The previous biggest purchase of Facebook was Instagram for 1 Billion in 2012.