Assassin´s Creed III
I think Valve dropped the game, due to the fact people have been getting a lot of invalid key messages from Ubisoft for their products bought from Steam.
Ubi have made it look like Valve's fault, but of course Valve is selling keys given to them.
[Edited by fullmetal5550, 11/29/2012 3:45:26 AM]
This article explains a bit about why:
It might help if I copy/pasted the correct hyperlink.
[Edited by shoresofexile, 11/29/2012 4:09:19 AM]