WebID is a replacement for traditional login on the Web. It is an open standard for identity and login. With WebID you no longer need to remember usernames or passwords for all of the sites you use. You can publish your identity wherever you want and choose what pieces of your personal information that you want to share with websites. WebID is compatible with OpenID, but is much more extensible. With WebID, logging into a website is as simple as selecting a WebID and clicking "log in".
WebID in Use
The following video gives a quick overview of how WebID is used in a browser.
Note that WebId can also be used between servers.
The WebID Community
The WebID specification is being developed and debated on the W3C WebID Community Group. Please don't hesitate to join and ask us about any implementation issues you come accross, problems with the spec, new implementations you have written that use WebID in one form or another.
If you are a developer, you may be interested in the latest WebID specification. Other pointers can be found on the Wiki.