A quote from their blog site: From Yahoo!'s perspective, any kind of signed-in customer engaging with Yahoo! solutions is a valued user, whether she verifies making use of a Yahoo!, Facebook, or Google ID.
Sign Into Yahoo Through Facebook
Login to Yahoo Mail account on PC/Desktop computer
First you require a username and password; now open internet internet browser from your computer/desktop. After that open web page www.yahoomail.com on it. To launch their new "one-click" sign-in just click on the "Sign in with: Facebook" symbol on the Yahoo! login screen. That's all you require; to obtain access of your Yahoo mail account.
Login to Yahoo Mail account on Mac computer system
If you are a user of Mac computer after that Safari must be your internet browser. Safari is the most effective surfing remedy for Mac OS; Safari fasts, faster and easy to use internet browser. You can quickly access your Yahoo Mail account with it. See, the best ways to login with Yahoo mail account on Safari internet browser. Simply open Safari and also type www.yahoomail.com; you will be routed to Yahoo mail sign-in web page. To start their new "one-click" sign-in merely click the "Sign in with: Facebook". You are then totally authorized right into Yahoo!
However, a suggestion- you still will not be able to sign into a mobile or desktop client using Google OpenID.
I hope this article could assist you. Thanks ...