The info URI scheme touts as a feature that info URIs are not URLs, so
tools (like browsers) won't try to fetch an info resource as if it were
a link, and info URIs can be managed independently of network resources.
On the other hand, there is an advantage to URLs in that the online
resource it references can describe what the URI is about. For example,
Dublin core URIs point to RDF descriptions of those metadata elements,
and XML namespace URIs sometimes point to RDDL documents explaining what
the namespace is for and providing links to more detailed information.
As to the second point, at least as far as MODS goes, there already are
web pages devoted to various element types. For example, why use