SmartMedia Pro - Smartmedia Pro Classroom Management Software allows remote-control of classrooms and virtual classroom management.
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.
NetSupport School - NetSupport School supports a teacher with a wealth of dedicated assessment, monitoring, collaboration and control features.
WowApp - Wowapp is the best alternative to Skype and you will get paid to use it!
CSE Classroom Manager - Technology for Education
Zulip - Chat for distributed teams. Zulip combines the immediacy of real-time chat with an email threading model. With Zulip, you can catch up on important conversations while ignoring irrelevant ones.