What social login aggregators like rpxnow do you know?

Question

User identification

I am writing some service and found out about the existence of such a thing as rpxnow.com.
It allows you to hang a widget on the site with login methods (facebook, google, etc.), from which the user can choose the one that is convenient for him. It remains for the developer (i.e. me) to get a unique identifier and username (as well as additional information depending on the method chosen by the user). Pretty convenient, but a number of shortcomings were discovered (starting from the inability to somehow customize the appearance of the widget and ending with the too frequent need for re-authorization).
So I wonder if there are analogues.

Answer 1

loginza.ru/