A buzz user who has a role of "Administrator" can create additional user accounts and have these accounts be "Regular Users" or "Read Only Users" and can share campaigns among all user types.
Regular Users can create, edit and delete campaigns.
Read Only Users can have access to campaigns but can not create, edit or delete them ... they simply are able to see the results of these campaigns.
An Administrator, when creating or editing a user's account, can also enable or disable outbound communication for the user. This setting is used only in the engage module. If outbound communications is enabled, this user will be permitted to initiate status message updates and other social engagement activities for the connected social accounts (twitter/facebook).