Simon wants a way of saying “This person has more information on this” in a link. Aquarius doesn’t think this needs XML, or a defined format at all. I agree. My solution to this is currently being worked into Epistula, and is this: Crossreferences.
You may have noticed (You may not have done) that my “Pingbacks” box has been renamed “Crossreference”, this is going to become more relivant as I start putting in my Referer tracking, categories, and linking systems, because all of them just get more entries in the Crossreference box (I’m currently using pingback internally for when I mention posts within posts). It needs no technology, just a place in the design for that kind of thing.