I'm thinking this could be part of the base class, so that that all export plugins benefit, but if that is difficult then just the XML plugin needs it:
The basic idea is to build a way to pump gradebook data out via http like a very simple web service.
So imagine some settings addded to the initial screen to:
Publish these grades via URL: [X]
Limit client IPs to: |__192.168.2.2, 188.8.131.52 _______________| (highly recommended)
Require password: |_snoopy123__|
If this checkbox is on, then the data is not sent to the screen and downloaded as a file like usual, instead you see a page which gives you the URL to access this data in a simple way, eg something like:
which can be cut and pasted elsewhere.