There are 1000 s of users that live inside CVW daily. Also needed survivability and robustness and multithreading in servers. For instance, white boards mostly have chat built in. JCS provides defaults so JCS-compliant whiteboard author does not have to also implement chat. No longer called a room so it can generalize to other collaboration metaphors.
People go to room or area of interest and see other interested people.
Here you are modeling your users. Each context has a conference manager. Some are automatically set up like chat role describes participant s responsibility and authority, socially. Another interpretation is that role restricts access rights. So if you want to assume a role, your access control will limit your authority.