Access Control Lists or ACL - manage who can see what content on your Web site and with who can create content and change content on the web site.

There are various levels of permissions for viewing content - guest, public, registered and special.

For control over adding/editing content either via the front end or via the admin you have guest, registered, manager, author, editor, publisher, administrator and super administrator.

For the majority of sites you should not need to alter the default ACL settings.