Through the end of 2011, Discover cardmembers will automatically earn double cash back (2%) on up to $250 in purchases each month at Amazon.com. Discover cardmembers who have a Miles by Discover or Escape card will earn double miles. There is no need to sign up for this promotion–cardmembers can simply use their Discover cards to start earning their extra rewards.

In addition, starting today Discover cardmembers can also use their Cashback Bonus to pay for their Amazon.com purchases by linking their card to their Amazon.com account. Since you’re only getting a 1:1 ratio of Cashback Bonus dollars to Amazon.com dollars, however, it isn’t the best redemption value. (Other gift cards offer a better exchange rate.) It does, however, offer a way to liquidate lower Cashback Bonus amounts, as there is no minimum redemption amount required when applying your Cashback towards an Amazon.com purchase.