OpenId is a way of authenticating yourself on the increasing number of websites that support it. OpenId itself looks like url address, something similar to "janedoe.openid.com". There are several OpenId providers you can get your OpenId address from, but wouldn't it be nice to have "yoursite.com" for OpenId instead of "somename.someopenidprovider.com"? Apart from looking cool, it's a good way to promote your site as your OpenId is often displayed in signature field even where other html links are disallowed.
