title: Need help in registration/sign-up (OAuth/OpenId with Facebook and Yahoo) and sign in
body: <p>I have an application that will accept both Facebook and Yahoo registrations as well as normal registration (providing username, email, password).</p>
  
  <p>I'm confused on the Facebook and Yahoo side of the registration. The scenario is, upon clicking the Facebook/Yahoo registration links, users will be redirected to the provider's site for login, then redirect to our site with a form pre-filled with their email address and other profile data (photo/profile pic, birthday, gender, address, etc). With OpenId, as far as I know, you can't have access to most of those information since its concern is authentication. So, on the signup part, I'm thinking of using OAuth. </p>
  
  <p>However, I saw on Yahoo's registration for an API key (<a href="http://developer.yahoo.com/oauth/" rel="nofollow noreferrer">http://developer.yahoo.com/oauth/</a> or <a href="http://developer.yahoo.com/dashboard/createKey.html" rel="nofollow noreferrer">http://developer.yahoo.com/dashboard/createKey.html</a>) that you can't access the user's email under Yahoo! Profiles. I need that email address to save on my accounts database.</p>
  
  <p>Then, on sign in, I plan to use OpenID both for Facebook and Yahoo. Is that ok? Using OAuth for sign-up, and OpenID for login/sign-in? Or can I use OAuth for signing in? (I know you can do this on Facebook with their Javascript SDK, but I am not aware about Yahoo's).</p>