"PC-exclusive effects and features" are in the pipeline for Ubisoft's Watch Dogs. It's just another title in their "unprecedented technical alliance".
Tom Clancy's Splinter Cell Blacklist and Assassin's Creed IV: Black Flag are also in the PC pact. Actual specific details about these enhancements will be "revealed in the coming months," say Nvidia.
Whilst at Gamescom, Nvidia visited the Ubisoft booth and got an overview of what Watch Dogs is. Sadly none of these PC enhancements were revealed.
Hopefully something substantial will be unveiled soon. It might be worthwhile reading up on Nvidia'sfor Splinter Cell: Blacklist as likely many of these named enhancements will make it over to Watch Dogs. Things like TXAA, HBAO+, tessellation, Parallax Occlusion Mapping and other technical sorcery.
Watch Dogs releases on PC, Xbox 360 and PS3 November 19th in the US, 22nd in EU.