I agree totally with @hpy about hosting and gardening another wiki. Many projects out there alreaedy have a wiki, and trying to maintain one for hackteria since 2009 has learned me a few things.
- For a group with a variety of interests, best to include your own stuff into a larger wiki, egg appropedia.
- For a specific project with a strong community, it makes sense to have your own.
- Stuff like hackteria commnity wikit hat doesnt have a single focus, never managed to have a large group of contributors.
And again, Discourse allows to use individial topics to be editatble as wiki. so i suggest to stick to this.