Hey,
We started looking into Semantic MediaWiki - it has impressive features.
But we got scared off by stories that it slows down the wiki too much. Maybe we should give it another look.
You _can_ abuse SMW in a way that it will kill performance on your wiki. If you use it in a sane fashion, it does not greatly affect performance. Sure there is room for improvement in some places, though it is certainly nowhere near being unusable due to performance issues, as i clearly demonstrated by many people using it very effectively. So though such stories due have a kernel of truth, they tend to be propagated by people not really knowing what they are talking about and tend to portray things bleaker then they actually are.
Cheers
-- Jeroen De Dauw http://www.bn2vs.com Don't panic. Don't be evil. --