Well, if they won't search for the answer via google, they aren't going to search for it in the wiki.
Well, it can be quite challenging to find answers for specific Excel issues via Google. Plus our wiki's database would be a lot smaller than Google's, and its content custom-tailored for frequently recurring issues, so there wouldn't be as many irrelevant results.
The key is not putting up a page on how to modify a doc. The key is putting the doc itself in the wiki. I know this doesn't translate really to spreadsheets, but you get what I'm saying.
Sure, but the workspace is polygamous; there's will always be many different applications, instead of one app to rule them all. And wikis certainly won't replace Excel any time soon. So if the doc itself is help for another app, that's valid wiki content... :)
-- Frederik