over on giantbomb:
Anyone who purchases the $399 Wii U Deluxe Set becomes part of a two-year (November 18, 2012 through December 31, 2014) promotion that will give consumers money back for making digital purchases. For every 500 points earned through purchases, you get $5 back. Pick up New Super Mario Bros. U for $59.99, for example, and you’ll have earned 599 points, enough to get $5 back.
Apparently there is no way yet for owners of the Wii Basic Set to opt-in to this promotion, so it seems like those who weren't able to get a Black Deluxe Wii U won't be able to take part.
Points can be used on the 3DS eShop, but purchases there won't count towards this points back system.
Finally, a website will be launched in December to manage your account.