Amazon's Xbox store launches with over 100 Xbox Live Arcade titles, ranging from Braid to Bejeweled 2. Hand over your dollars--not Microsoft Points--and Amazon will instantly give you a code to add the game, Points or subscription to an Xbox Live account.
Games will benefit from the usual Amazon features of reviews, ratings and wishlists, increasing exposure and bringing a more traditional retail angle to games previously available only through the Xbox Live Marketplace--a very few retail releases aside.
This also gives a quick and easy way to gift Live Arcade Games. It was at one point possible to gift Microsoft Points in the US if you knew their Live ID, but not actual games.