This is pretty amazing, but I wish they picked a better name for it. I have a feeling that a good amount of people will dismiss it just because of the name.
What's wrong with the name? Some cultural reference I'm not getting?
It can always be rebranded later on
What's wrong with the name? "WhatsApp" sounds pretty dumb to me, too, but it's entrenched in the social consciousness, so we don't really think about it.
(The name even has nothing to do with chat; originally WhatsApp was a way to share your "current status"; "WhatsApp" sounds like "what's up?".)