Interesting timing: I just got an e-mail for a (free) app that I purchased in the Amazon app store. Only problem, I have never visited the Amazon app store. The Amazon rep on the live chat explains to me that this is because someone entered their e-mail address incorrectly when making a purchase. How does that make sense? Shouldn't you need to be signed in to your Amazon account (or some other account) to make an app purchase? It actually makes you type in your confirmation e-mail address manually? Can someone with experience in their app store comment? That seems like a brutal design decision...