I think on the whole that this is a good idea; I do wonder if it might harmfully divide the effort on the documentation rather than provide a complement to the manual and guide, but I think the best way to find out is just to try it and see what people use.
If the existing FOSS designed to fill this niche are unacceptable to our purposes we can always make our own. Such a site would not be complicated to build, and I would be very willing to put in effort toward this goal. I do not know Elisp very well, which prevents me from contributing much to this project even though I depend heavily on Org-mode, but web programming I can contribute. -- A. Ryan Reynolds