I'm fully ready to admit this is not my area of expertise, which is why I thought I'd throw this idea out before putting too much effort into it. I don't think there is a built-in export function, but all the posts are stored as XML in a single file, so it shouldn't be hard to scrape the content if desired.
I also confess ignorance as to how standard the markup language is. Perhaps any contributions should stick to plain text if possible to aid future conversion.
The markup is more or less standard. Some adjustments will, however, need to be made before porting. The posts can be extracted pretty easily.
However, I would not recommend this, except as a very basic start up, because the single file in which everything is stored grows in size pretty fast.
Some (including myself) have suggested that a rationality wiki would be a useful supplement to this site. In the spirit of getting things done, I set one up here: http://rationality.tiddlyspot.com/ The password to save edits is omega.
The TiddlyWiki framework it uses is very lightweight and won't be satisfactory as a long-term solution. I do think it has potential as a minimalist beginner's guide though, and could serve us well for the time being. I am not very knowledgable about wiki software in general, but TiddlyWiki has served me well for multiple personal wikis. I planned on developing it a little further before revealing it to the community, but other commitments demand my attention. Please feel free to contribute.
Comments, suggestions? Is it better to start with something that can handle a significant user base and future growth, or should it stay small and self-contained to remain accessible to beginners?
Update: I think it's becoming clear this can't serve as more than a short-term hack, even for a minimalist beginner's guide. At least it is provoking discussion. I'm still hoping for contributions so we have a leg up once an official solution emerges. If you do contribute, please try to keep markup to a minimum to facilitate a future conversion.