Since we're talking about wikis (even ones that won't admit they are secretly wikis, you'd think they were afraid to be thrown out of the country if the secretly admitted to being open community software) I looked around to see if it was really true that there weren't any good hosted wiki services around.

There's plenty of hosting plans including wikis, but there's also Schtuff, which is free, simple, has history (with differencing in the same style as writeboard), access control, search, backups, and much more.
They could do with a fresher look and bigger fonts, but other than that it looks really nice. Bookmarked.

Other free options are here.