This is an interesting query. I have set up a couple of web based solutions for this type of thing.
The first uses Joomla with a jfusion bridge to integrate dokuwiki. I also installed agora which is a Joomla native forum component. Users of this site post questions in the forum and answers are hyperlinks to pages in the wiki or answers in the forum are copied there. The results of user interaction on a site like this can be open to public viewing should you wish it.
The second solution I have come across is software called Opengoo. It is designed to be a project manager with forum and wiki capabilities too. I think this may be your best bet as the first solution has been a bit awkward to set up for me. I don't think the public can view or access the files and results of user interaction created in Opengoo. Please correct me if I am wrong.
Hopefully these two options will widen your options