EduDo - EduDo is a video discussion platform
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Courseroot - Biggest online course database on the web
WhatsApp - WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.
TeenUp - A learning platform designed for teens by teens
Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.