If an image sent to Kotaku is to be believed, ACIII will get plenty of post-release content. Players will be probably be able to pick up a Season Pass for all of the content at a discounted rate. Here's the note to Gamestop employees:
Hi Team GameStop!
First things first - a BIG thank you for helping us ASSASSINATE our announcement pre-order goals! We could have done it without your hard work. As a token of our appreciation, inside is an exclusive necklace from the Assassin's Creed team in recognition for all you do.
What's next? We are currently in the process of creating a complementary development team that will begin working on post-launch episodic content to continue the Game of the Year experience that Assassin's Creed 3 will undoubtedly deliver. With a dedicated team specifically to this content we plan to set the bar for quality DLC in our industry.
We know you're familiar with the "Season Pass" concept and, beginning shortly, we'll start to take preorders of our very own. We'd love your continued assistance in informing pre-order customers that a better value is available for those who pre-order Assassin's Creed with the "Season Pass."
Once again, thank you for everything and we'll be in touch soon.
-Assassin's Creed Team