I think informal conventions should work fine.  We don't need to set up a
naming authority.  If the impelmentors do this, and authors do this, and
standards bodies stick to this convention when defining new link types
for industry-specific applications, I think we can keep it all straight.
I can only think of one or two vendors who would not consult the list
of common types before inventing their own, and even Mic... er I mean
even these vendors, would not want to deliberately break documents.
And probably would want to put some kind of free-advertising prefix on 
the links they implement.  There is more than enough incentive to
steer clear of naming conflicts.  It's the 'accidents' we have to
worry about.
-- Craig Hubley Business that runs on knowledge Craig Hubley & Associates needs software that runs on the net mailto:craig@hubley.com 416-778-6136 416-778-1965 FAX Seventy Eaton Avenue, Toronto, Ontario, Canada M4J 2Z5