Real estate question: should GST be paid when buying land in Canada?

A reader was asking me to find out if GST should be paid when buying land in Canada. I've done some research and found a very good document on the Government's web site.

There are a lot of points and exceptions, but from what I've understood, you always have to pay taxes if the land was used as a business (except if it was a farm). Any private sale by an individual is exempt of taxes. There are also cases where a non-taxable land can switched to taxable by the owner ... but that's where my interest in taxes wizardry fades :-)