I've started working on semantic wikis again. We're planning a study here at work to see whether semantic wikis can be used to create content suitable for reasoning. We don't know either way yet, I suspect the answer is going to be mixed.
Our platform is mediawiki. We have installed the semantic mediawiki and semantic forms extensions. The software is a bit cumbersome to use, but we've been able to define some forms, templates and content for our study. We're still waiting on a version of the Halo extension that works with semantic mediawiki 1.0.
I've found the idea of a semantic wiki intriguing and promising ever since I first heard of them. Now I'm getting the chance to study how well the idea works in a near ideal environment, and where it falls short. This is also the first project I've put together. I'm really hoping it goes smoothly, I'd like it to lead to some interesting follow-ons.