One of the things the last five years has seen is an explosion of wiki software. This isn't necessarily a bad thing: yes, there's a lot of crap (Sturgeon's law and all), but there's also some useful specialization. Not to mention a slew of companies bringing non-hierarchical, open documentation to the corporate world and actually making money doign so. (Or trying to.)
But is there a wiki that works well with distributed, disconnected workers? Such a system would allow me to grab the selected wiki content (the full thing, a branch/web/section, whatever) and run a local server on my laptop. I could then edit the content as normal and when I'm done, sync it back up with the main server. Of course there may be overlapping edits, but smart merge software (of which there's lots) and a good interface should be able to make that workable.
I've been using OneNote at work recently and it's not bad. The client is simple and its data are stored in simple files rather than a database. It apparently has good support for working in a tablet (handwriting support, etc.) but I'm not using one now, still holding out hope that Apple will make one with OSX...
Syncing is done with normal XP filesystem tools that have no special merge capabilities; since there are only a couple of people editing the pages merging isn't a big deal. But this clearly won't scale beyond a few people. Apparently there's support for WebDAV in the current version, with better support in a new version coming out later this year. I haven't played with that yet so I don't know how well it works.
But I do really like a smart client vs using a web browser to edit a page. So it seems that a smart client for editing wiki pages locally that can sync up to a server where people can edit them with a web page is the best of all worlds.