If your site has a password-protected area, you can create user accounts in Site > User Manager or allow individuals to register for access themselves. When a user account is created it is placed into a Group. Groups open or restrict permissions for logged in users. The Groups available for users accessing the front end of your site are:
The default for any new user registering on the front end of your site is Registered. You change this by editing a user record in Site > User Manager.
"Registered" and "Special" Access Levels
In addition to the privileges inferred by the names of these groups, the ability to view articles, menu items, modules, events, tickets, products, or Salesforce elements can be set based on these Groups. For each of these items, you can select their Access Level to be Registered or Special.
Choosing Registered will allow all those in the above list to view the item.
Choosing Special allows only Authors, Editors, and Publishers to view the item but not Registered. Author, Editor, and Publisher users can view everything available to Registered users. Registered users can only view that which is set to Registered.