Re: tag URIs (was Re: New Intro to RDF)

Danny Ayers wrote:

  This reminds me, perhaps you can save me trawling the docs. The URI
> for every property I've ever seen uses the http: scheme. But is the
> http: scheme actually mandated anywhere in the specs?
> 
> It does make sense to use http: URIs, it's useful to have something
> available on the Web for those URIs. (It looks like a RDDL doc at the
> ns URI might be the something favoured by the TAG:
> http://www.w3.org/2001/tag/issues.html#namespaceDocument-8 )
> 
> But is it The Law?

My understanding was that :

"[A] URL is a type of URI that identifies a resource via a 
representation of its primary access mechanism (e.g., its network 
"location") rather than by some other attributes it may have. Thus as we 
noted, "http:" is a URI scheme. An http URI is a URL."

The source of which was the "URI Planning Interest Group, W3C/IETF" and 
the link to which I've since lost. Perhaps this has been superseded by 
another spec. (I hope not because the above is pretty straightforward to 
my eyes.)