Actually, what you mention was part of Ted Nelson's original vision of hypertext, but it never got implemented in those whole 'World Wide Web' thing.

I'm actually surprised that Google doesn't work for this, as much of their search engine is based on the concept of citation counting. (example -- How (not) to ask a question, searching by node id. You get NO results if you also add in 'site:perlmonks.org')

I like the idea ... and in theory, once you've indexed the site, you only need to update the links as nodes are modified. (although, for sake of completeness, you'd need something that could recognize [id://...], [node title], or a direct HTML link (and the direct link might be to perlmonks.(org|net|com). [node title] is the trickiest (or <a href...> using a node's title), as the target of the link when the node was written may no longer match the current destination of the link.

Of course, I have no idea how difficult it'd be to actually implement or maintain something like this.