I was playing the Crackdown 2 demo at E3 and I saw there were these little cards on the demo kiosk for something called "Chuck's Ducks 2 Beta", with a user name and password to sign up for it at www.chucksducks2.com
So I went to the website and it turns out it's a Facebook game. It didn't look like it had anything to do with Crackdown 2 at first, it has a cutesy carnival games art style. It's a basic 'Same Game' colored block matching game clone, clearing a board of balloons earns you ducks, then it goes to a little shooting gallery minigame that's like reverse Duck Hunt- you shoot hunters popping out of the grass who are trying to shoot down your ducks. 
Oh, and the ducks are flying into Pacific City. Which is the only Crackdown reference I can find in the game. 
There's a 'Facebook Duck Total" counter on the side that says it will unlock something in the Crackldown 2 demo when it is filled. So I guess that's the whole point of this thing.
It just seems really random and stylistically different from Crackdown. I mean there's a hundred things they could have made a web game about that would have more to do with Crackdown 2... taking out gangs or running over zombies or whatever... but instead it's about popping balloons for ducks? Maybe there will be something in the game that makes sense of it.

well there is the quacker bomb, basicly a rubber duck in the demo thats locked, so maybe it unlocks it

Yeah now that the demo has come out it makes sense... kinda