Gamers World

According to a leaked letter from Ubisoft to GameStop stores, Assassin's Creed 3 will have DLC following its launch in October.
The letter, outed by Kotaku, was a "BIG thank you" to GameStop for helping Ubisoft achieve their Assassin's Creed 3 pre-order goals, but further on the letter indicated plans for post-release DLC.
"We are currently in the process of creating a complementary development team that will begin working on post-launch episodic cotnent to continue the Game of the Year experience that Assassin's Creed 3 will undoubtedly deliver," the letter detailed. "With a dedicated team specifically to this content we plan to set the bar for quality DLC in our industry."
The letter didn't specify if it would be single player or multiplayer DLC, but the fact that it's episodic content makes me believe it will further expand on the single player campaign. Although I'm sure we'll see the typical multiplayer skins and maps, as well. The document mentions a "Season Pass" concept, which the company will begin taking pre-orders for soon.
"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'".
As a side note, GameStop also received an exclusive necklace from the Assassin's Creed team "in recognition" for all they do. I suggest you ask to see it next time you find yourself in a GameStop.