I got my pincode via a postcard. The postcard listed discounted prices for value resorts during certain timeframes. I almost tossed it out because we don't stay at value resorts. Also the pincode was printed in small text and at first I didn't even spot it -- the postcard looked like a generic mailing advertising discounted prices at value resorts. For some reason, I just set the postcard aside rather than tossing it in the trash.
A few days later I read here on the boards that someone who got that same postcard was able to use the pincode on the card to book a deluxe resort. I took a closer look at the card and finally spotted the pincode. So I called and booked YC at a discount.
So I learned two valuable lessons. First, examine any mailings from Disney very carefully and second, never assume that any discounts they tell you about only apply to the one resort category they mention in the mailing!