RDF predicate for Disco

Since HTML and Atom have link elements explicitly mentioned in Eran's  
discovery draft, I was wondering how that might map to RDF documents.  
It seems that many XHTML rel types have predicates defined here  
<http://www.w3.org/2005/05/hrel/>. Of course in <http://www.w3.org/TR/ 
powder-dr/#semlink>, POWDER defines the predicate for its  
rel="describedby", using <http://www.w3.org/2007/05/powder- 
s#describedby>. I'm not sure this is a perfect match, since its range  
is a <http://www.w3.org/2007/05/powder-s#Document>.

But the real question is who cares? Does anyone feel the need to have  
this kind of link today?

Which begs further, what is the right way to extend disco to allow  
future document formats that want to have internal links for  
rel="describedby" that could be used for discovery?

http://josephholsten.com