The Watch Dogs special edition contains bonus in-game content:

Breakthrough pack Untouchables Pack DedSec single players pack Chicago south club pack

In Watch Dogs, this system is called the Central Operating System – and it controls almost every piece of the city’s technology and holds key information on all of the city’s residents.

You play as Aiden Pearce, a brilliant hacker and former thug, whose criminal past led to a violent family tragedy. Now on the hunt for those who hurt your family, you'll be able to monitor and hack all who surround you by manipulating everything connected to the city’s network. Access omnipresent security cameras, download personal information to locate a target, control traffic lights and public transportation to stop the enemy…and more.

Use the city of Chicago as your ultimate weapon and exact your own style of revenge.

http://watchdogs.ubi.com/watchdogs/en-us/game-info/