some details may not be correct, but in short, it was a promotion disney offered to entice people to come around late aug/sept.
if you bought a package including staying at a disney hotel at full rack rate and at least a one day base ticket for everyone in the room, disney would throw in the dining plan for free.
the dining plan (DDP) in 2007 included a table service meal each day, including appetizer, entree, dessert, non-alcoholic drink and tip.
the DDP in 2008 will not include an appetizer and a tip for table service meals...which has been a problem, since 2007 participants didn't expect to have to pay for them...
if you got free dining in 2007, you could have committed to returning in 2008 and disney would promise you the free DDP then (called the "bounceback" program). at that time, though, disney didn't explain that the "free" DDP would be different in 2008.
it remains to be seen whether disney wants the hassle of a world full of people stiffing their waiters because last year tips were included and they still want their "free" dining...