[Ivaylo Draganov]

a wiki-plugin already exists:

https://bbpress.org/plugins/topic/wiki-post/

a revision tracking plugin also:

https://bbpress.org/plugins/topic/edit-history/

But it seems like it does much more than we basically desire.

I just tested the Edit History plugin and it does indeed track all that data – last edit, last editor and number of edits. But it does not output the message in the normal topic view. Instead it uses a separate page with all the revisions of a post. And that page is not visible to everyone.

I guess it is not hard to add that feature to the plugin. Wish I had the programming skills to do it!