The code specifies dates, which differ a bit from value to moderate to deluxe. It basically covered January 6th thru early February, end of March (3/30) and first week of April, and August 10th-late September. There might have been a few dates in early May, but I don't remember. Sorry that I can't be more specific.
20% off values, 30% off moderates. Our resort flier didn't mention deluxes at all, but we asked and got a great discount (40% off) at Wilderness Lodge.
I don't know if they'll still be taking reservations in December. We were at Pop from Oct 13th-23rd, and we didn't receive the flier until Oct 20th. In other words, it's a very recent offer.
Redemption date begans August 10th.