Ubi appears to be taking multiplayer serious in Watch Dogs. The bit I found particularly interesting:

Or you can grief someone – ram into them with a car when they’re trying to stop a crime, for example.

Original URL:: http://blog.ubi.com/watch-dogs-multiplayer-e3-2013-preview/

Watch Dogs – Hacking into Multiplayer - UbiBlog - Ubisoft®
Just like the Chicagoans in Watch Dogs, we were caught off guard when we were hacked in the game. This time, though, it was another player who was after us. Multiplayer revealed!