When setting up your system, it behooves you to visualize how the system will be perceived by the average user. If your system is too convoluted and difficult to use, the users will go elsewhere. A BBS with no users really doesn't have much point to it.
Group accounts are special forms of user accounts that contain many users. There are a number of access limitations that can be imposed via group access, and group accounts can be the recipient of mail, which then gets routed to all members of the group.