How whatsapp become a worldwide Messaging App?

[Grandson]

More than 2 billion people in over 180 countries use WhatsApp to stay in touch with friends and family anytime, anywhere. WhatsApp is free and offers easy, secure, reliable messaging and calling, available on phones around the world. Now it also has released the updated versions like yo whatsapp, Fm Whatsapp, gb whatsapp from gb funda etc. All of these version has more features than original whatsapp.