In my country, we use our own social networks, the best one of them is Zing Me, this social network allows me to log in with a Facebook account, a Yahoo account, a Twitter account, a Google+ account. I wonder how this can be done?
Could you please explain to me the mechanism or give me some helpful link for this?
Your help would be highly appreciated! Thanks!
PS: In fact, it guides me through some steps for creating new account based on the personal information which is fetched from the outside network (E.g: Facebook). And this is the secret thing I want to know, how can it fetch information of a user from an outside network?