Facebook:

• App ID
• App Secret.
• Click here: https://developers.facebook.com/apps for instructions.

Google+:

• Client ID
• Client Secret
• API Key
• Click here: https://developers.google.com/console/help/#generatingdevkeys for instructions.

Yahoo:

• Consumer Key
• Consumer Secret
• Click here: https://developer.yahoo.com/oauth/ for instructions.

Twitter:

• API Key
• API Secret
• Click here: https://dev.twitter.com/web/sign-in/implementing for instructions.