For one thing, you can't ALWAYS get the same discount from a lot of other sources.
If vendors are using the discount codes to track where to spend their advertising dollars, and they aren't getting the accurate information they're looking for, then they will discontinue offering it.
And as I said, it has happened that people get to a rental counter or front desk without the appropriate coupons, postcard, etc., and find out at that point, ON their vacation, that they are not entitled to the discount.
If Disney's DVC site states that it is for MEMBERS ONLY, requiring a password and user name, then certainly Pete would have the integrity not to allow that information to be posted here.
Those were my points.