I think what Kenny refers to is deducting the deprecation of the business use part of your house as capital cost allowance. The CRA link I posted earlier says:
"The capital gain and recapture rules will apply if you deduct CCA on the business use part of your home and you later sell your home."
Whether it applies to the whole house or only the claimed business part of it, I don't know, I'd assume the latter but that's just a guess. I also don't know if you can still deduct regular expenses like property tax, utilities, insurance etc. as a homeowner even if you decide not to claim any deprecation.
I rent so it doesn't apply to me and I can simply deduct part of my rent, hydro, internet, and tenant insurance as business-use-of-home expenses. Ah, renting, makes life so much easier! ;-)
Re: financial advice on a mountain bike forum: I've gotten some useful stuff out of this thread over the years, also a lot of unuseful stuff. That's how internet forums work, signal-to-noise ratio is low and you need to filter out the noise. I take the useful stuff as pointers to look into further. For tax stuff, I always start at the CRA website, often I can find everything I need to know right there.