OpenID is a simple way to log in to websites. It’s a great idea because you don’t have to remember a separate password for every website you log in to. Also, you have more control over how your personal information is used by the sites you visit. If you have an OpenID, you can log in to any website that supports OpenID logins (like stikis does). You can log in to stikis and use it in exactly the same way that someone registered locally would.
See this blog post for an informal introduction.