How does it work?
(1) You sign up at Bing Rewards
(2) You Download the Bing Bar
(3) Sign in using your Windows Live ID
(4) Complete a basic registration process
Then you start to accrue points towards getting rewards in exchange for those points.
The main thing you need to know is you need to be running Internet Explorer and have the Bing Bar running at all times.
Just a few months ago, Bing discontinued the Cashback program citing a lack of "broad adoption that we had hoped for." I wonder if they really think this program will make much of a difference or maybe they aren't expecting "broad adoption" this time around?
Forum discussion at WebmasterWorld.