Publish a set of Wiki pages and attachments, as specified by the QueryPlugin, to a user defined directory, on some user-defined schedule. The directory could be made publicly accessible. In essence the Wiki could be used to author content that the PublishPlugin then (duh) publishes for read-only public consumption.
NOTE: baseURl would need stripped out or modified in the published HTML so relative links would work as expected. Interwiki links could be problematic too. Hmm, if the original Wiki was secured appropriately there wouldn't be any need of this plugin would there be?... Or would there?... maybe?... --JohnV
See Ideas for some discussions that give context to this plugin.
You could do this now with wget

Hmm, I use wget on a chron to "ping" our running wiki's. It never occured to me to actually use it for this... But... The files you get won't be usable will they? I mean I couldn't point a browser at the gotten files and read and follow links, all links would route me back to the live site. I want something more javadoc-like where all links are relative. Unzip to a directory and off you go. Also wget would pull all the live site rendered "stuff" like LeftMenu, the SearchBox, etc. I want the page content only, no edit link, no more history link, etc. So wget is similar in spirit but not quite what I'm after. --JohnV
On a semi related note, I pull my site down to the Palm Pilot using AvantGo, so I have a read only version with me. It does not pull the attachments down. -- FosterSchucker