All users belong to roles. Each role represents a set of permissions that get applied it’s The Default Role
By default Vanilla comes pre-set with 4 roles:
http://www.example.com/role_icon.jpg
The role icon will replace the user’s icon on all comments and the account page. If you do not supply a value for this field, the user-defined icon will remain (if one exists).
When you’re creating a new role you will be presented with all of the options described above, as well as being asked to select the categories this new role should have access to. Note that this will not disrupt the way in which categories are managed after setting this access list. Unless otherwise specified under Category Management, this role will have access to any new categories you create after setting a new role. This option simply removes the extra step of having to go into Category Management and telling Vanilla which roles are allowed in what category.
Deleting a role is simple, just click the little (X) next to the roles name, and you’ll then be asked to define a replacement role to take it’s place. So when you remove a role from the system, users who currently have that role will be shifted onto the one you’re now replacing it with as the role you delete gets wiped from the database.
If you have permission to manage roles, you can see a “Change role” option in the panel when viewing a user’s account profile. Click this link and you will be presented with a role-changing form.