OpenID and OAuth are authentication and authorization protocols that allow users to verify their identity and grant access to personal data across different websites and applications. OpenID is used for authentication by verifying a user's identity, while OAuth allows users to grant third-party applications access to their account information without sharing credentials. Many major websites like Facebook, Twitter, and Google implement these protocols to allow sign-in and data sharing between platforms. Developers can also add support for OpenID and OAuth through open-source libraries for various programming languages.