Actually, I have the following question:
How to return users who have logged in through Facebook?
On our website you have the option to login via social. media (fb & vk), from which we take the interests of users and would like to take their emails for information alerts.
But the fact is that policy IB Vkontakte, it does not give the API a list of emails of its users (well, okay, spammers, I'm afraid). It turns out that a very effective mechanism for the return user in this case is not available...
What you have to offer?
I must say that to suggest forcibly the 2nd step enter the email address, as do some websites — we believe fail'ohms. While considered only a reminder option that it would introduce soap as on groupon. Perhaps there is a more elegant solution?