Access Management System for Websites

Any active user will be given a logon account which is tailored for their needs. Whenever they make changes to the site it is recorded and visible to administrators
Users can be assigned roles which define the parts of the system which they are able to change. In this way you will always know who can change what and what changes they made
A similar control applies to the end-users of the site. They may be 'anonymous' and only be able to view selected pages or you can allow logon accounts so they can add comments, upload files and see otherwise hidden parts of the site