On 2016-01-27 14:31:53 ghostwrita said:
It's iMessage or voice.
And you probably need to check the "more than half the world" thing :).
iMessage is essentially whatsapp done by Apple. It doesn't use the GSM protocol. If all your friends are using Apple devices that explains it. Whatsapp simply takes it one step further and works on all current devices.
And maybe "half the world" is a bit of an exaggeration but 450 million people were using it when Facebook acquired it back in 2014. They have seen substantial growth since then, so it's a pretty significant number of people, only a tiny fraction of which are using it exclusively for "shenanigans".