Paul has volunteered (was Re: Overloaded URIs must GO!)

Hunter, David dhunter at
Mon May 31 16:44:34 BST 1999

David Megginson writes:
> The phone number for my business is 1-613-722-4697.  Let's say (for
> the sake of argument) that my credit card number is 161 3722 4697, and
> that my Social Insurance number is 1613 7224 697 (it wouldn't be,
> because Canadian SIN's are only nine digits long, but just pretend).
> Now, is there any problem with the fact that my business phone number,
> my credit card number, and my SIN are digit-for-digit the same?
> In principle, the same thing applies to using URLs as unique
> identifiers -- I (should) always know whether I'm dealing with a link
> or a namespace, so there should be no room for confusion: links point
> to resources that can be retrieved, and namespace URIs do not.
> Last year, while Namespaces were being designed, some people argued
> (quite intelligently, as it turns out) that the REC should explicitly
> state that there is nothing to be retrieved at the other end of a
> Namespace URI; unfortunately, RDF does confuse the Namespace URI
> (which cannot be retrieved) with the schema (which can be), so the
> waters get unnecessarily muddy.

Okay, this all makes sense; if we're treating our URL as a URL, then we know
that there is only one document at that location, and if we're treating our
URL as a URI, then we know that our namespace is unique.

BUT, even given this, this still seems like a hack to me.  If HTTP is the
"hypertext transfer protocol", then shouldn't it be used to transfer
hypertext?  The example above isn't <em>quite</em> the same, because there
is no protocol attached to the beginning of those numbers.  (e.g.,
VISA://16137224697)  It's kind of like saying that because your VISA number
is unique we could use it to identify you (assuming that you are a
"resource"; yes, we <em>could</em> start calling you VISA://16137224697, but
that's not really what the VISA:// protocol is for.  OTOH, using
SIN://16137224697 makes a bit more sense, because a Social Insurance Number
is designed specifically to uniquely identify someone.

Just like HTTP is designed to retrieve documents, and some other protocol
could be used for namespaces.  (I am, perhaps, completely misusing the word
"protocol", but I hope my meaning is getting through...  :-)

David Hunter
david.hunter at
MediaServ Information Architects

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