I know that InterWorx sends out messages to users when they’re close to reaching their account quotas, etc. - however - the server administrator is never notified as a part of this process…
More insight into accounts getting near their quotas in the form of an e-mail would be a pretty useful feature I think.
This feature is available but just disabled by default (this option will be exposed in the web interface in the next release). You can turn it on by editing /usr/local/interworx/iworx.ini and changing