This option allows you to provide reseller users with additional Webmin features beyond the Virtualmin Virtual Servers module. Be very careful with this option, as most Webmin modules default to providing dangerously complete control over the services they manage. There are, however, occasions when it can be very useful. For example, if you have a custom module that provides some service specific to your environment, you may find this option very valuable. Further many modules can be configured with very strict access by default, or you could clone a module and configure it with a very specific set of functions to make it safe for use by all resellers. You can selectively grant additional privileges to some reseller users using the Webmin Users module.