I did the same with my app Piclr too. I have a timed expiry as I found people do not immediately sign up. Still tweaking it a bit. True now the email is a singl

I did the same with my app Piclr too. I have a timed expiry as I found people do not immediately sign up. Still tweaking it a bit. True now the email is a single point of failure, but 2 factor will help here. (https://itunes.apple.com/app/id889978045 https://itunes.apple.com/app/id889978045) Improving the world - with one password less at a time :-)