Still, Whatsapp has extremely high penetration in some countries outside the US. E.g. in my country of origin (The Netherlands), 9.8 million people use Whatsapp

Still, Whatsapp has extremely high penetration in some countries outside the US. E.g. in my country of origin (The Netherlands), 9.8 million people use Whatsapp, 7 million people daily (of 17 million inhabitants). I now live in Germany, where Whatsapp had 30 million active users in 2014 (population: 80 million). If people have some other messenger it's typically Facebook Messenger. tl;dr: there are a lot of countries/language regions where Whatsapp is the absolutely dominant messenger.