I think a key point of David's original post, which I would like to
emphasize, is that if I use a URL to refer to a web page, the owner is
generally either readily visible (in the URL) or discoverable (via
domain lookup). When I represent a term as a URL, it is at least known
who is serving that URL; and often the _developer_ of the term can be
derived intuitively (e.g., by dereferencing the URL in a browser).
These are positive social outcomes, and encourage further adoption of
the term.
When I represent a term as a URN or other URI that can not be
dereferenced directly in a browser, almost all of that social context
is lost. The responsible party can be found only by manually parsing
the URN, going to an obscure (to most) web page, manually looking up
the URN authority. The developer of the particular term may be
discoverable from the rest of URN -- but any semantics embedded in the
rest of the URN, if any, can only be known by finding and reading the
materials from the application of the responsible party. And the
actual metadata for the term can only be found by discovering, through
close analysis of the application or some other way, a 'magic lookup
URL' so a browser can look up the URN and provide additional
information about it.
It isn't that these problems can't be solved; eventually global URI
resolution will probably be available with browsers thanks to tricky
and consensual underlying technologies. But the initial
specifications as rolled out provided no standard way to solve them,
so until the marketplace converges, the social conventions available
with URLs are not supported.
I would quibble with some of the details of David's original
argument. Someone other than Company X can have the companyx.nnn
domain, for example. And semantic systems could use 'term rank'
methods to derive the most important URI for a term like 'microsoft',
thereby achieving at least one of Google's neat tricks in the semantic
realm. But overall, the adoption of semantic and other URI-based
technologies in the human world will inevitably lag that of http URLs,
until the technologies are so fully developed that all these
'weaknesses' (strengths in other respects, of course) are fully
addressed.
john
On May 18, 2009, at 1:31 AM, Tim Berners-Lee wrote:
David,
On 2009-05 -18, at 07:20, David Huynh wrote:
Sherman Monroe wrote:
[...] For example, when I search for Microsoft on Google, the first
result not only IS what I want, but also LOOKs like what I want. I
can make the decision to click on it within maybe 1 or 2 seconds.
The URL "www.microsoft.com" in that search result is perhaps the
most convincing element, as I know only *the* Microsoft can
possibly own that domain. (This will be a challenge for any SW
search engine, because no-one can own any URI, and so, seeing a URI
alone means pretty much nothing. That's one of the main differences
between URL and URI, which is usually swept under the rug.)
I had to pick up in "no-one can own any URI".
First of all, terms: URL is not really a term in the architecture
of the WWW. I find it best to use "URI". "URL" does occur in the
browser UI, but in the specs it has been used for various things,
often a derogatory term for a URI which might change. How are you
using it here? To mean the URI of a web page?
To mean an " http:" URI? If not, then why are you dealing with
URIs which are not HTTP URIs (tch, tch! :-)? If so, then why don't
you think these HTTP URIs in the semantic web are owned?
Why can't the semantic web track 'whois' information of domain
ownership, and maybe even SLL certificate information, of sites and
be aware of the social relationships, and use them intelligently?
(perhaps more safely than a human who will be confused by http://www.microsoft.com.1000ripyouoff.crime/
?) . It is true that the delegation of information within a site
is not typically made explicit (though it could be with site
metadata). But there is in general a system of ownership of URIs,
it seems to me, and it is important on the SW in the social
processes by which different groups get to define what different
terms mean. So "no-one can own any URI" set off a red flag for me.
Tim
John
--------------
John Graybeal <mailto:[email protected]> -- 831-775-1956
Monterey Bay Aquarium Research Institute
Marine Metadata Interoperability Project: http://marinemetadata.org
