W3 Uid Home
The following picture shows the process to establish stable interdomain Web links by a URL example:
Only the Site ID is registerd on the resolver (1). The second ID is used as an argument for the concatenated URL it delivers on a Web request (2). The target system "sites.google.com" can find the resource by using both IDs.
In this case also the final resource is given a UID. Thus it might be possible to find the addressing document by an Internet search engine or in dedicated directories, if the document migrates to a different container. At minimum one known resolving domain is necessary. These lookup domains can also be organized in a federated way.
In the meantime the resolved target URL of the picture was changed, but without impact to all clients using http://w3-uid.net/w3-1352540680041-uid-tmappsync/... URLs.
Currently, in draft status all unknown site links are resolved to this page.