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RE: PURLs don't matter, at least in the LOD world

From: Young,Jeff (OR) <jyoung@oclc.org>
Date: Fri, 17 Feb 2012 14:24:26 -0500
Message-ID: <52E301F960B30049ADEFBCCF1CCAEF590F71141B@OAEXCH4SERVER.oa.oclc.org>
To: "Hugh Glaser" <hg@ecs.soton.ac.uk>, <public-lod@w3.org>
Hugh,

I commonly use PURLs when I'm modeling RDF vocabularies as described
here:

http://www.w3.org/TR/swbp-vocab-pub/#purls

This allows me to prototype the vocabulary on my workstation without
concern for where it ultimately ends up. Any instance data I generate
along the way will remain unaffected since I've used PURL as the
vocabulary namespace.

Jeff

> -----Original Message-----
> From: Hugh Glaser [mailto:hg@ecs.soton.ac.uk]
> Sent: Friday, February 17, 2012 1:48 PM
> To: public-lod@w3.org
> Subject: PURLs don't matter, at least in the LOD world
> 
> (Sorry if there is a paper/discussion on this that I have missed
> somewhere. And I may have some of this wrong, as I have essentially
not
> used PURLs.)
> M Scott Marshall and others' comments have prompted me to put pen to
> paper and ask what the list thinks on this.
> 
> It has long puzzled me why people seem to think that PURLs (and
> Handles, etc.) solve some actual problem.
> Leaving aside the question of whether it actually adds extra fragility
> as to whether purl.org will continue to exist.
> (Personally I would bet the Library of Congress will last longer than
> purl.org, but I would have to wait too long to collect on the bet to
> make it worthwhile.)
> 
> In the Linked Data world, at least, what does a PURL give protection
> from?
> 
> Let's say I have http://dbpedia.org/resource/Tokyo. I can:
> a) Use the URI without any URI resolution at all, and it is really
> useful to do so (as commented, foaf:name is used a lot, and it does
not
> depend on anything being at the other end to resolve to);
> b) I can resolve to find out what DBPedia thinks it "means" (returns
as
> RDF);
> c) I can use it as an ID for another source to find out what that
other
> source thinks it "means".
> 
> Now let's say dbpedia.org goes Phut!
> What I lose is facility (b)
> 
> What happens if I have http://purl.org/dbpedia/Tokyo, which is set to
> go to http://dbpedia.org/resource/Tokyo?
> I have (a), (b) and (c) as before.
> Now if dbpedia.org goes Phut!, we are in exactly the same situation -
> (b) gets lost.
> 
> Both of these situation can be fixed by persuading someone (the
> registrar for dbpedia.org or the purl.org organisers respectively) to
> allow someone else to take over purl.org/dbpedia or dbpedia.org
> respectively.
> But once dbpedia.org goes Phut!, you get a dead link whatever you do,
> until someone takes it over.
> 
> Not much to be gained for the overheads of having the purl?
> 
> I can see that in the Web of Text, a URI that has gone 404 is rather
> painful.
> And I know that people who have curated data find dying links painful,
> and seem to find Handles etc some sort of comfort for their concerns,
> even though they don't necessarily solve the perceived problem, in my
> view.
> But in the Web of Data, given a good guess at somewhere else (such as
> the LoC, or even the Virtuoso endpoint or sameAs.org), I stand a good
> chance of finding a skos:*Match or even an owl:sameAs that will get me
> back on track again.
> 
> Is there something I am missing about PURLs?
> 
> Best
> Hugh
> --
> Hugh Glaser,
>              Web and Internet Science
>              Electronics and Computer Science,
>              University of Southampton,
>              Southampton SO17 1BJ
> Work: +44 23 8059 3670, Fax: +44 23 8059 3045
> Mobile: +44 75 9533 4155 , Home: +44 23 8061 5652
> http://www.ecs.soton.ac.uk/~hg/
> 
> 
Received on Friday, 17 February 2012 19:25:46 UTC

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