WhatsApp > Telegram > Matrix
A brief introduction on how to start using open solutions instead of being binded to closed proprietary applications.
1) Start with WhatsApp, the popular messenger used by billions around the world.
2) Introduce Telegram Messenger, used by millions around the world. (is not much popular in India)
3) Both the above applications are proprietary, but good.
4) Introduce the open source federated cross platform messaging application