Google/Yahoo/StackExchange/Flikr sign in with OpenID works exactly the same way that Facebook login works (to the user.) Your site presents a button, the user c

Google/Yahoo/StackExchange/Flikr sign in with OpenID works exactly the same way that Facebook login works (to the user.) Your site presents a button, the user clicks it, and if it's the first time they get a popup asking to grant access, then they're logged in. Those four domains are pretty far reaching in terms of casual and technical users but now you can also provide a third option for even more technical users to use a custom OpenID, for virtually no additional cost in development.