Stephen Downes
Stephen's Web
About OpenID on Stephen's Web
What Is OpenID?
OpenID is a system that allows you to have one identity that you use on any number of websites.
This way, you don't have to fill in user information and other details every time you want to create an account (or to simply comment) on a new website (at least - that's how it will work in the future when the 'attribute exchange' protocol is settled).
How does it Work?
You create an account on an identity provider website. The identity provider website provides you with a URL. This URL is your OpenID identity.
Then, when you want to login to a new website, look for the small OpenID logo 
in the login form. Type your OpenID into the form and click the Login button.
When you click the login button, the new website sends you back to the URL you provided as your OpenID identity. That's where you login, at your OpenID provider. If you successfully login, then you are returned to the new site.
What's the point of this? The idea here is that you prove that you are the person who is able to log into your site. If you keep your password secret, nobody else can prove that they're you - and you can prove to anyone else that you are!
Where Do I get an OpenID URL?
From an identity provider.
Stephen's Web is not yet an identity provider (that's phase 2) - and even when it is, you may want a site that's a bit more reliable.
Here is a list of OpenID providers (I selected LiveJournal).
Websites
Whatever happened to...?
You're probably thinking of mIDm, a distributed login system I developed a little while ago.
It was based on the ideas in my paper Authentication and Identification. The idea was that a system that let people self-identify was good enough for the web; that all these systems that demanded some sort of authentication were asking too much.
After all, the person who should benefit from a login system is you, not the people who are requiring the login.
Anyhow, a few days after I launched mIDm, Brad Fitzpatrick of LiveJournal launched OpenID based on the same principles and using almost exactly the same mechanism (the really big difference was that I wanted people to put their URL in their browser header).
OpenID is the system that caught on. Which is perfectly fine with me - I've always seen OpenID as a validation of what I was saying at the time (and am still saying today), and I like to think of mIDm as a validation of what Brad Fitzpatrick was - and is - still saying.
And nobody owns OpenID, nobody's demanding licensing, and nobody's forcing you though a single point of login failure, which is exactly the way it should be.
