A quote from their blog: From Yahoo!'s viewpoint, any kind of signed-in user involving with Yahoo! services is a valued user, whether she authenticates using a Yahoo!, Facebook, or Google ID.
How To Login Yahoo With Facebook
Login to Yahoo Mail account on PC/Desktop computer
First you need a username and password; currently open web browser from your computer/desktop. After that open web page www.yahoomail.com on it. To start their new "one-click" sign-in simply click on the "Sign in with: Facebook" symbol on the Yahoo! login screen. That's all you require; to obtain gain access to of your Yahoo mail account.
Login to Yahoo Mail account on Mac computer system
If you are a user of Mac computer then Safari must be your internet internet browser. Safari is the most effective surfing service for Mac OS; Safari is quick, much faster and also easy to use internet browser. You could easily access your Yahoo Mail account with it. See, how to login with Yahoo mail account on Safari web browser. Merely open Safari and also type www.yahoomail.com; you will be routed to Yahoo mail sign-in page. To initiate their new "one-click" sign-in just click on the "Sign in with: Facebook". You are after that completely authorized right into Yahoo!
Nonetheless, a recommendation- you still will not have the ability to authorize right into a mobile or desktop computer client making use of Google OpenID.
I hope this article can help you. Thank you ...