Telegram is a popular free Instant messenger application...

Telegram is a cloud-based mobile and desktop messaging app with a focus on security and speed.

Telegram is a popular free Instant messenger application that can be used to chat with your friends all over the world.

Telegram is free forever, no ads, no subscription fees.

Telegram is available for many different platforms, including Linux, Android, iOS, Windows Phone, Windows, and Mac OS X.

https://telegram.org

Install telegram on Mint 17, Ubuntu 14.04

$ sudo add-apt-repository ppa:atareao/telegram
$ sudo apt-get update
$ sudo apt-get install telegram