Is Maine the same as California?
Currently when you do a search on the Canadian Board for the Prairies it tells you that this is a new board and for more info check out the Atlantic Provinces board. This is like suggesting that people in San Francisco should check out the Northern New England board. This reference makes no sense what so ever.
The boards for many areas were compressed to a ridiculous degree for many, many years. Finally the Engineering folks created new boards, but the huge archives are still tied to the old boards. That suggestion is simply reminding folks that, if you are looking back in time for something older then you need to go to the old board to access the appropriate archive.