Wikis and educational wikis and spelling wikis

We have been looking at some of the technologies and so I have joined some educational wikis. They're interesting in that they seem to be alot like forums in terms of building a community but they're different too.

The difference is that in addition to threaded discussions, there's an ability to collaborate and create a nice set of documents. Other than that, with the threads and profiles, it's a very similiar collaborative tool.

Has anyone created an spelling wiki? More specifically, a wiki on teaching spelling? I think that would be an interesting approach to encouraging collaboration on SpellingCity.com. I start by creating a spelling course which we encourage everyone to give input to.

But, spellingcity.com - if it ever becomes operational - is joomla based. Is there a joomla wiki technology?