A quote from their blog site: From Yahoo!'s point of view, any signed-in user engaging with Yahoo! services is a valued customer, whether she authenticates using a Yahoo!, Facebook, or Google ID.
How To Sign In Yahoo Using Facebook
Login to Yahoo Mail account on PC/Desktop computer
First you require a username as well as password; now open internet browser from your computer/desktop. Then open web page www.yahoomail.com on it. To launch their brand-new "one-click" sign-in merely click the "Sign in with: Facebook" icon on the Yahoo! login display. That's all you need; to get gain access to of your Yahoo mail account.
Login to Yahoo Mail account on Mac computer system
If you are a customer of Mac computer system then Safari need to be your internet internet browser. Safari is the very best surfing solution for Mac OS; Safari is quick, much faster and easy to use browser. You can quickly access your Yahoo Mail account with it. See, ways to login with Yahoo mail account on Safari internet browser. Simply open Safari and type www.yahoomail.com; you will be guided to Yahoo mail sign-in page. To initiate their new "one-click" sign-in simply click on the "Sign in with: Facebook". You are after that completely authorized right into Yahoo!
However, a recommendation- you still will not be able to sign into a mobile or desktop computer customer making use of Google OpenID.
I hope this article could aid you. Thanks ...