any Suggestion may be appreciated :DI'm surprised this isn't more obvious? Does Yahoo even provide the ability to get a users e-mail address after OAuth / proper permissions? I see at least 3 posts on the forum asking this question and no decent answer. The url suggested to Mail API Examples doesn't work.
With that, users can sign into your web site with their Yahoo! OpenID and you can use that to identify these users. Because we support the OpenID Attribute Exchange (AX) extension, you can also request for user's name, email address, profile pic, gender, timezone, and language preference during the sign-in flow. You can check this post for details: