In the short term, a search feature for the forum might do the trick. I keep resorting to Google to find old threads which is less than ideal.
But in the long term, I agree that something like a wiki would be quite valuable. We shouldn't have to keep searching for old items. If pg did it as part of the site, maybe editing could be granted with a minimum point threshold to provide some level of protection from spam/graffiti. Plus pg, rm, etc. could exercise more control over some of the core info.
And I agree that doing it in Arc, while unnecessary, would be valuable in putting more pressure on the language.