I looked at chatango and I think the intended use case is a bit different than dropinchat. Drop-in chat provides user-to-user instant messaging. As best I can tell, chatango (primarily?) provides broadcast style communication. Is this correct?
The documentation on dropinchat.com mentions "groups" as a set of users which are allowed to see one another and message back and forth. Our team thinks this use case might be helpful, for example, for a website administrator to limiting communication between members on a given organizational team or individuals in a certain building, etc.