Administrators (most have a host license):
Can edit Channel settings, access the billing section, add hosts, change subscriber privileges, and remove subscribers from a channel. The difference between an Admin and an host is that an Admin is normally the person who created the channel, and can access the Billing section of your channel's plan. A host cannot access the billing.
Hosts (most have a host license):
Can edit the Channel settings, host & create webinars, change subscriber privileges and remove subscribers from a Channel. They cannot access the Billing area of the channel.
Presenters (must have a host license):
Can be added as presenters to webinars and can create webinars. They do not have host or admin privileges within the Channel plan.
Can interact with admins, organizers and other subscribers, watch and attend webinars. They are basically a member of your channel, with access to webinars you have hosted. They can be removed and added manually within the subscriber section the channel. Admins and hosts can access the subscriber section within the channel settings.
If made visible, subscribers will appear within the member section of a channel.