OpenBoard - The OpenBoard software is an interactive white board software.
Zoom - Equip your team with tools designed to collaborate, connect, and engage with teammates and customers, no matter where you’re located, all in one platform.
Conceptboard - Instant Whiteboards for Teams & Projects
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
IDroo - A shared whiteboard for use by multiple Skype-users simultaneously. Features
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.