Linkbases and "Document Enrichment"

Hi,

Here's another use case for link bases, I'm afraid I'm behind on 
this list, so apologies if someone's mentioned it already.

I've always assumed that when people talk about link bases 
they're usually assuming some form of coupling between the 
source material and that link base. i.e. the link base is basically 
the links from the source material factored out into a separate 
document thereby allowing the links to be described in a richer 
fashion.

A twist on this is where the link base and document are authored 
independently. The document can then go through an "enrichment" 
process to tie it into the link base, allowing the reader to navigate 
to more resources than were originally specified in the document.

This might involve textual analysis of the original document e.g 
to pick out identifiers, key phrases, etc.

PubMed do something similar to this with their Linkout feature:

http://www.ncbi.nlm.nih.gov/entrez/linkout/doc/linkoutoverview.html

This is effectively a link base that can be used to enrich scientific 
papers with links to related articles, journals, even gene sequences 
and the like.

In a way I suppose this is using a link base as an annotation feature.

Do people commonly do this kind of thing?

Cheers,

L.

p.s. stable linking in general is a bit of a hot topic in the STM area, 
with features like DOI (http://www.doi.org) and CrossRef (http://www.crossref.org) 
being commonly used. These are probably off-topic here though.