I guess it's a local Bulgarian thing (and I guess many of you don't even know where Bulgaria is on the map

) but here a messenger called Viber is very popular and even some big companies use it to avoid SMS charges and sending their messages through Viber, such as e.g. delivery companies sending delivery status updates, banks sending statements and transaction notifications, etc. It's very bloated app that I hate but is still much better than WhatsApp and has been offering end-to-end encryption and edit/delete of sent messages for ages. Not sure if it's popular outside Bulgaria though...