Phil Windley wrote this introduction to XRIs and i-names. Other than a minor error in stating that i-names are not reassignable (they are, but the underlying i-numbers are not), it's great to have i-names be presented in an accessible way. Making i-names seem simple is important to those of us integrating them into our solutions. Folks will gradually discover that there's more under the hood than they realized. But they have to get one first.