Most of the people I help with basic tech support questions have never heard of the Wayback Machine, and odds are that people who ask themselves the same questions in the future won't have heard of it either. I feel it's petty to take back information from people who have trouble finding it kust to spite the big guy, especially since I already went to the trouble of putting it out there anyway. And it being available elsewhere, while a good thing, is not a guaranteed good thing. Forums and wikis can close or be vandalized or go through what's happening to Reddit now or any number of other things.