With the "Role Manager Plugin" you can manage Roles and Capabilities of your WordPress-Blog.
Please use this plugin with care, because all changes you make, are persistent. This means that if you deactivate the "Role Manager Plugin" your changes stay active!
The "Role Manager" adds four pages to your blogs users menu and an additional fieldset with capabilities on a single users profile page. For using the "Role Manager" a user needs the capability "Manage Roles" in addition to the "Edit Users" capability.
When using "Role Manager" a single user can be a member of only one role. The maximum length for a role-name is 30 characters. Only letters, digits and spaces are allowed. You can't set a role-name equal to an existing capability-name.
An "attached role" is a role with one or more assigned users.
A role with no assigned users is a "detached role".
The maximum length for a capability-name is 30 chars. Only letters, digits and spaces are allowed. You can't set a capability-name equal to an existing role-name.
If a capability is asigned to a role and no users are assigned to the role it is considered a "detached capability".
The capability isn't assigned to any role but is assigned to one or more users as an extra capability.
Unused Capabilities are not assigned to any role or any user as an extra capability. Only this kind of capabilities can be removed by using the button "Purge Unused Capabilities".
Places where you can find more about the System of Roles and Capabilities in WordPress: