Phil Windley blogged about FreeYourId.com, a full service OpenId provider that gives you access to services off of a single .name URL. This starts to give a taste of what i-names can do, though it is - while clever - somewhat simplistic. When you give someone a YourId.name email address, they can then email you forever, as long as you keep the email it forwards to current.

When you give your i-name, you can remain in control over what services others can access from it. So if someone - or some company - starts sending you messages that you don't wish to receive (solicitations, spam, etc.) you can easily shut them off and they no longer can contact you via that vector. Add a layer, and you could allow messages into your inbox that are considered to be of high quality from some group you trust. Or you can provide authentication that you are someone's "friend" as they move between social networks, but when the go to a network you don't like, the authentication no longer works.

Such mediated services are a major aspect of what make i-names (and XRI) particularly interesting, and the OpenId folk have (IMO) wisely include XRI service discovery in the OpenId 2.0 specification, which is nearing completion. Because of the complete control i-names give their owners, they provide a simple and natural foundation for creating the next killer app: community mediated reputation services.