My latest project is to create a way for students and faculty to mark up documents on the web without a lot of infrastructure. This is part of a free-form portfolio project, where we worry mostly about saving hyperlinks so we can find things later and less about actually storing the objects themselves. One nice thing about this is that the creator (the student) has complete ownership over her creation, and can see it as something other than "just for class" work.
As an example, we could ask our students to sign up for a google account and create a google doc. These can be published to the web, like this one I created (from a screenplay). If you have a diigo account, you should be able to see the markups I put on it as well.
A second method is a bit more ambitious. I figured that we might want more control over the documents sometimes. We might not want students to have to worry about google accounts, for one thing. We also might want to keep copies of some kinds of work more private and store them on local servers. Students can all use word processors and with a little help can produce rich text files (RTF) rather than more complex varieties, like (shudder) docx.
With a little CGI magic we can create a drop-box service where RTF files get morphed into HTML files (web pages). The advantage of that is that then they can be marked up with diigo. This should work locally (at least it does in my tests), but could also be on a public web site using authentication.
So I built one. You can can see a converted RTF here (notes for a short talk I gave at the new library opening). If you're logged into diigo you should see the markup on it too. You can try it out for yourself by browsing to the plain upload page and submitting an RTF file. The conversion is far from perfect. Not all kinds of markup and formatting come over. Bold did, and numbered lists, but not hyperlinks or graphics. I think I can overcome some of this with time, working with the perl module that performs the magic.
All in all, this was a successful experiment. With modification, it could becomes a repository for RTFs and hyperlinks, which in combination with all the resources of the web, become an unlimited platform for providing coursework interactions.