> I believe, was a key component in getting huge amount of users in 3rd countries. In the UK as well. Although many people have free effectively-unlimited SMS

> I believe, was a key component in getting huge amount of users in 3rd countries. In the UK as well. Although many people have free effectively-unlimited SMS in the UK, this costs £ and not everyone has. Also consider that international SMS are charged at extortionate rates, and I know some teenagers who have busted through the limit of "unlimited" SMS. And so, the introduction goes: "I'll text you - do you have Whatsapp? Oh :(". This social pressure has driven almost everyone onto the service. And people have kept using it because it's just as functional and less restrictive than 160 characters.