It doesn't sound like part of the deal was for 1-click defaults to be changed. It sounds like there was an assumption this would happen implicitly by giving it

It doesn't sound like part of the deal was for 1-click defaults to be changed. It sounds like there was an assumption this would happen implicitly by giving it to everyone, but they underestimated how many Discover card users were already on 1-click: The promotion was structured in a way where anyone with a Kindle, who used their Discover card to buy a digital good (e.g. mp3 or movie), would get a $10 Amazon Gift Card. The reason the good had to be digital is because to buy a digital good you need to use your 1-click default card, and Discover’s primary objective for this promotion was to get users who had a Discover card, to make it their 1-click default so Discover could be the card of choice for holiday shopping over the course of the fourth quarter. That was the only way Discover could justify spending $10 when someone ordered a $1 .mp3 music file.