The range of possibilities does not differ from what we find, e.g. in Skype. Chime in the basic, free version Basic supports chat (instant messages) and voice and video chat between two people.
The Plus version for $ 2.50 per user per month, adds the ability to manage Active Directory, 1 GB of user message space and the ability to connect your own domain.
The Pro version introduces group video conferencing, screen sharing and unlimited VoIP connections - but we'll pay you $ 15 per user per month.
Currently, you can try the Pro version even without adding your credit card for 30 days, after this period we will be switched to the basic version, or by paying a subscription we will stay with the possibilities of Pro.