Authentication and Authorization for Google APIs - Google Code
API Documentation | foursquare Developers Apps connect with foursquare via OAuth 2.0 . This is the standard used by most major API providers, including the Facebook Graph API. Start by registering your app to obtain its foursquare API credentials. Be sure to use an account with a secure password to own these credentials. If you're creating an app on the behalf of a full-fledged company, consider creating the key in association with the page account for your company. Since each set of credentials is tied to a particular URL, you may want to create different credentials for your development server and production server.
Connect with Viadeo | Viadeo API
Sign in with Twitter Updated on Wed, 2012-09-26 12:20 Place a button on your site or application which allows Twitter users to enjoy the benefits of a registered user account in as little as one click. Works on websites, iOS, mobile and desktop applications. Features Ease of use - A new visitor to your site only has to click two buttons in order to sign in for the first time.
Facebook Platform enables you to make your web site more social. You can use our Social Plugins , such as the Like Button to drive user engagement with a single line of HTML. Our Login Button and Registration Plugin let you simplify or eliminate your own user registration and sign-in. Lastly, the Graph API lets you access the full social graph of a given user, allowing you to create a truly deep personal experience.
A Better Way to Sign In