Of course, since the user already went over the "hill" and downloaded or maybe even paid for the app, they will be unlikely to back out. They've already put in

Of course, since the user already went over the "hill" and downloaded or maybe even paid for the app, they will be unlikely to back out. They've already put in effort and they don't want it to go to waste. The most powerful tools against annoying web signups are the back button and bugmenot, in that order. Neither exists for the iPhone. Amazing that you are not cargo culting a signup screen. Maybe save the email address once they first input it.