When buying books at Amazon you only have to enter your creds once, so that's not really an issue. What people tend to forget is that developing "apps" on the

When buying books at Amazon you only have to enter your creds once, so that's not really an issue. What people tend to forget is that developing "apps" on the iOS platform is automatically restricting your market to those who have or can afford the devices it runs on. Just because the business model worked on the web for Amazon, does not mean that you can build an "app" for a closed platform owned by a competitor and get similar results.