A quote from their blog: From Yahoo!'s perspective, any type of signed-in user engaging with Yahoo! services is a valued customer, whether she validates using a Yahoo!, Facebook, or Google ID.
How To Login Yahoo With Facebook
Login to Yahoo Mail account on PC/Desktop computer
First you require a username and password; currently open web internet browser from your computer/desktop. Then open page www.yahoomail.com on it. To initiate their brand-new "one-click" sign-in just click the "Sign in with: Facebook" symbol on the Yahoo! login screen. That's all you need; to get access of your Yahoo mail account.
Login to Yahoo Mail account on Mac computer
If you are an individual of Mac computer then Safari must be your internet internet browser. Safari is the very best surfing remedy for Mac OS; Safari fasts, faster and easy to use internet browser. You could conveniently access your Yahoo Mail account with it. See, the best ways to login with Yahoo mail account on Safari browser. Simply open Safari as well as type www.yahoomail.com; you will certainly be guided to Yahoo mail sign-in page. To start their brand-new "one-click" sign-in simply click the "Sign in with: Facebook". You are after that completely signed into Yahoo!
Nevertheless, an advice- you still won't have the ability to authorize right into a mobile or desktop computer customer utilizing Google OpenID.
I wish this write-up could aid you. Thanks ...