I think you have a point with the registering user retention problem. Nothing is more painful than typing a password on a phone (especially if you use strong enough passwords).
But this very first step (I'm talking about choosing a nickname and password, not the social connection step) is clearly something derivated from what we do in browser apps. We could do that better on mobile apps.
For example, launching an app for the first time could generate some random login and password, and let the user instantly play with the app. When we consider he had enough time to get the picture, we notify him he must choose a password to be able to login from other devices, and he should probably choose a nickname to customize his experience.
But this very first step (I'm talking about choosing a nickname and password, not the social connection step) is clearly something derivated from what we do in browser apps. We could do that better on mobile apps.
For example, launching an app for the first time could generate some random login and password, and let the user instantly play with the app. When we consider he had enough time to get the picture, we notify him he must choose a password to be able to login from other devices, and he should probably choose a nickname to customize his experience.
That would be way more mobile friendly to me.