Ok, from what I understand, Disney's doing this:
* Offer is going to 300 to 500 people. These include in-park guests, and past WDW visitors who are being solicited via email.
* The emails may be targeted to people who used their Keys to the Kingdom card to pay for meals at buffets, on previous WDW visits.
* Two different offers being tested, both in the Animal Kingdom as far as I can tell:
- $15 for one all-you-can-eat meal at a counter-service restaurant.
- $25 for two all-you-can-eat meals at counter-service restaurants.
Disney's also running a host of other tests on things like rooms, tickets and meals, essentially to "see what sticks." More details on that soon.