You're being hacked, Aiden, and not by the AI.
Ubisoft's dystopian future cyber warfare title Watch Dogs will have multiplayer, and the developer's gone into some detail telling the world how it will work. You'll always be Aiden, all the time, but so will everyone else; you just won't be able to tell, because all the other Aidens will be tagged with an NPC skin. Thus immersion is preserved, while at the same time allowing 'Aiden' to take center stage in the ongoing drama. Moreover it won't intrude into your ongoing story if you don't want it to, as it can be turned off, and in any event multiplayer is automatically disabled when you're on a mission.
"We see an alert on-screen saying Aiden is being hacked," Ubisoft describes in its blog post. "Quickly, the number jumps to 14% infiltration." What to do? Well, first you trace the hacker - no easy task - and then you've got to confront your opponent directly. If the virus installs before you can get in there and deal with your opponent, you've got a real problem on your hands. Or maybe you'd prefer something more subtle in your multiplayer, like just being on onlooker while the other player goes about the on-screen action. A little bit of cheerful griefing - like ramming his car with yours while he's driving around town - is also an option. Some multiplayer missions offer tasks like protecting another player while that player's on a mission, among other non-adversarial actions.
Watch Dogs is currently scheduled for a November 2013 release on current generation consoles and the Wii U, and will also be released on Xbox One and PS4 when the next generation finally launches.