How to deploy a StackExchange-style question and answer site for a university subject?
Yes it's possible. Yes it's been done. There are plenty of StackExchange clones such as OSQA to use - there's a question over on meta-stackoverflow that lists them. You can pretty much pick your favourite platform, and there will be a StackExchange clone for it.

But:

You might well find that take-up rates are very very low (maybe one in 20 if you're lucky). And you need a lot of people to give a Q&amp;A site enough critical mass to sustain itself.

They're all reasonably easy to use, for the end-users. As to how hard they are to install and maintain, that's a question of the kit and talent you have available. If you've already got a server serving Django apps, then OSQA is easy. If you've got a *AMP stack, then any of the PHP clones should be pretty easy.  Installation and management is the really easy part of the process. Drumming up, and sustaining, partcipation is the really hard part.