I find it really funny how many people here in the US pontificate on the usefulness of Whatsapp, when in fact in much of the world, whatsapp is basically a daily feature used far more often by people than SMS, telephony, or anything else. Not to mention how quick the adaptation rate is/was. I recall in the Netherlands Whatsapp went from being new, to something like 80% penetration in a period of something like 3 months, and the value(s) of Dutch telecoms operators taking a significant hit due to that at the time.