Basically Rocket.Chat is built like an IRC client; you can connect to various public channels or create private conversations for groups or individuals.
Moreover Rocket.Chat can be personalized by many different add-ons and modules, e.g. a Bot. By using WebRTC video conferencing, VoIP calls, and files can be exchanged and initiated.
The registration on our Rocket.Chat is currently possible.
For more information on the course Rocket.Chat page