[img src="" caption="" credit="" alt=""]
Cashback has created a Facebook app to bring you deals, and pay you money if you buy through its partnering merchants.
Deals are offered up from several merchants, including Amazon, iTunes, and many more. Recent deals will show on your Facebook profile page, and friends can view and click them for more details. This won't navigate them off of Facebook, but will go to another page within Facebook that lets them peruse through even more deals if they like. From there, users can pick which deal they'd like to purchase. Cashback will show the percentage rate for the average amount of money you'll probably get returned to you once the transaction has been completed. With your Cashback acount, you can choose the payback threshold at $10, $20 or $50.
This seems to be a native Facebook app, as there is no Cashback site independent of its Facebook offerings. That being said, you won't need to register for anything separate with Cashback, though you will need to provide some personal information in order for your check to be mailed to you.
Another native Facebook app is X Me. See also: 30+ Awesome Facebook Applications