6. Ingress
An excellently innovative, first of its kind MMOARg, Ingress allos the usr to join a faction and fight over dominance of the world by accessing portals and "hacking" other players to get their XM. It's fun in its own right but also simulates the kind of movement based technology location access found in Watch Dogs.
5. NFC
The Watch Dogs Exposed trailer shows how the protaganist needs only "4 seconds and a clear signal" in order to get information from a targets phone. Recent technology called NFC allows devices to pair when in close proximity and share information and as
this video and
this article demonstrate, it can be used to get more than just superfciial data from an unsuspecting target.