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Re: @itemid and URL properties in schema.org

From: Daniel Dulitz <daniel@google.com>
Date: Wed, 9 Nov 2011 10:44:49 -0800
Message-ID: <CACWrOGZsuPLu5o+M=XFMLjpcV0X66-hHL1-215YTG1r=AkW6=Q@mail.gmail.com>
To: Dan Brickley <danbri@danbri.org>
Cc: Toby Inkster <tai@g5n.co.uk>, Gregg Kellogg <gregg@kellogg-assoc.com>, Jeni Tennison <jeni@jenitennison.com>, Jason Douglas <jasondouglas@google.com>, "public-vocabs@w3.org" <public-vocabs@w3.org>, Guha <guha@google.com>, HTML Data Task Force WG <public-html-data-tf@w3.org>
That was what I personally hoped for from the url property: a lightweight
way to refer to a thing in a practical sense, without an author having to
worry about extensionality/intensionality, just "if my viewer clicks on
this link will they see something that makes sense to them as being about
this thing?" Further links to descriptions of the thing, or identifiers for
the thing, may be found at that page.

I understand that expert users may sometimes wish to distinguish between
strong identifiers and weak ones, and personally (not speaking for Google)
itemid could be a way to do that. But I'd envision that as something that
only experts would do, and then only to achieve specific agreed-upon
results from systems that consume the data. Perhaps a useful analogy for
what I envision is "strict mode" for a parser.

This is vague because I think there are few concrete systems that would
need to make these tradeoffs (due to data quality issues, etc.).

On Wed, Nov 9, 2011 at 05:26, Dan Brickley <danbri@danbri.org> wrote:

> On 9 November 2011 14:14, Toby Inkster <tai@g5n.co.uk> wrote:
> > On Sat, 5 Nov 2011 10:43:45 -0400
> > Gregg Kellogg <gregg@kellogg-assoc.com> wrote:
> >
> >> Alternatively, schema:url could be a subProperty of owl:sameAs, which
> >> after a fair amount of reasoning can yield what you want (in RDF that
> >> is). If schema:url really is used to designate the subject, much
> >> better to use @itemid in the first place.
> >
> > Based on the examples at schema.org (for instance, the example at the
> > end of http://schema.org/Person), schema:url is basically the same as
> > foaf:page or rdfs:seeAlso, not owl:sameAs. Perhaps even foaf:homepage
> > (which is an owl:IFP, and thus an indirect identifier).
>
> Or foaf:isPrimaryTopicOf, even? If the thing pointed to is a doc
> primarily about the thing.
>
> This seems to be a variant of the eternal perma-thread of RDF:
> deciding where and how we care to distinguish between identifiers for
> things versus more conventional pages that describe those things. In
> it's hash-versus-slash guise, it had people advocating (largely
> unsuccessfully) for Web server reconfiguration to send http 303
> redirects.
>
> As an online discussion grows longer, the probability of someone
> mentioning URNs, "URLs not being for identifying real things",
> map-vs-territory and http-range-14 approaches 1.
>
> All that aside, it's a pretty common pattern to identify things
> indirectly via pages about them; the question generally is how
> explicitly we handle the indirection / proxying.
>
> http://www.imdb.com/title/tt0083658/ is my favourite movie, etc.
>
> Maybe I should've said http://en.wikipedia.org/wiki/Blade_Runner ? Or
> searched around and found http://dbpedia.org/page/Blade_Runner ? Or
> realised that this was a 303 redirect from the real deal,
> http://dbpedia.org/resource/Blade_Runner ...?
>
> We need markup idioms that allow for people who don't have the time to
> chase down "URIs for the real world thing" every time. Maybe
> schema:url is for that; I don't know, I wasn't there at the
> beginning...
>
> Dan
>
>
Received on Wednesday, 9 November 2011 18:45:47 GMT

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