Most sites, when you register via e.g. Facebook, redirect you to a page afterwards asking you to enter additional information that the site needs. Very often this includes setting a password for the site.
I don't understand why this is the case.
I am creating a site, and want to allow the user to register either via e.g. Facebook, or create an account directly on our system.
- If they've registered via our system obviously they have set a password, and there is a settings screen once they've logged in where they can connect their account. My plan would be, from then on, then could log in via Facebook.
- If they've registered via Facebook, they can obviously log in via Facebook. If they like, they could set a password in the settings screen later. That would allow them to log in with their email address (that we get from the Facebook login) and their new password. Or they could never do this, and continue always logging in via Facebook.
Is there a problem with this approach? Why do other sites force you to set a password on their site after you've registered via a social network?