Is it possible to restrict registered users to a specific email domain? (like .edu?)
 
Or possible to restrict downloads to only registered users? (forcing a registry before browsing, moodle does this)
 
These issues are coming up with school systems in regards to who can access the site...
 
(students being able to download homework with answer keys, etc)
 
Another semi-related issue is that some school districts I have emailed are actually claiming to hold an All Rights Reserved copyright over the educational materials that their teachers create, prohibiting them from sharing on a site.