This is very powerful tool for offering special pages to clients or to CMS administrators.
Put all your cpanel admin pages here, aggregate all applications related to the CMS here like dotproject, roundcube webmail, etc.
This goes a long way toward helping CMS administrators unify the digital world of the CMS community, whether it's commercial, NPO or personal.
You can associate your users with different custom login types (cpanel, roundcube, dotproject, wikis, etc.) and assign each user a unique pw to that application.
Some Issues:
Passwords stored in msyql as cleartext - not secure
The login options are somewhat confusing, documentation is limited, considering each application has its own settings and may be finicky about being wrapped in an iframe.
Some logins by Joomla user don't work, whereas if you hardcode the single-signon user/pw it does work. Needs a bit more work there.