Bumping this old thread to help others (and to hopefully hear what other stores have worked for you!) I live in the U.S. and have the Chase Aeroplan card. While many of the offers do not work for me (example: a store will not accept my address) some do. I have been able to successfully use the following stores and get points through the portal:

Apple (My favorite use of the portal; I ordered a refurbished iPhone for pick-up at my local Apple store)
Madewell
Sephora
Macy's

I have not had any luck anywhere else.