ok, CCRA released the new guidelines for ecommerce in september.
http://www.ccra-adrc.gc.ca/E/pub/gm/b-090/b-090-e.pdf
Basically here is the jist of the 32 pages:
For affiliates:
if you get paid for advertising a company's sites/product and they aren't located in Canada or registered in Canada for a GST number, you are providing a zero-rated service. 0% GST, you can still claim tax credits. If you're canadian and use Canadian sponsors, you pay GST on the paychecks you get.
For paysite owners:
Tricky.
According to that paper, if you sell membership to a website and allow users to view/access/download content that isn't your intellectualy property (trademark, patent copyright) then you have to charge/pay PST. From what I saw there, content that is your intellectual property then you are qualified for a 0% rating. It's usually when you do your own billing or have a merchant that you would would be under this braket.
Now it can be argued that you provide a service to ibill ccbill, who are non residents/non registered businesses, to allow their customers to access your website in which case you would qualify to the advertising exclusion. It's IBILL that bills the customers and you get a % of the sales (85-89%).