- From: Dan Brickley <danbri@danbri.org>
- Date: Tue, 23 Oct 2012 08:25:51 -0700
- To: Michael Hopwood <michael@editeur.org>
- Cc: Ed Summers <ehs@pobox.com>, Cord Wiljes <cwiljes@cit-ec.uni-bielefeld.de>, "public-vocabs@w3.org" <public-vocabs@w3.org>
A few observations - * We want all Things to be identifiable using URI/IRI/URL identifier notations * In the HTML5 the specs use 'URL" rather than "URI"; at launch Schema.org's primary notation was HTML5 MIcrodata, so we inherit that usage. But Schema.org also targets mainstream developers and publishers who often are not so familiar with 'URI' or 'IRI', but feel they know what an 'URL' is See http://developers.whatwg.org/introduction.html#willful-violation http://developers.whatwg.org/urls.html HTML5's usage of 'URL' is explicitly in terms of URI and IRI and the notion of a 'resource' * In RDF, we use 'resource' as a synonym for Thing (ie. all things can be considered resources), rather than something like 'http-accessible-information-object', which seems to be some people's reading of the term. I think Schema.org is closer to the 'thing' reading. * Microdata has an 'itemid' attribute, for Thing identifiers (analagous to resource= in RDFa Lite), see http://www.w3.org/TR/rdfa-lite/#resource for the RDFa version. * The use of schema.org/url is broadly equivalent to using itemid or resource attributes from Microdata and RDFa; it takes the items Web identifier and expresses it explicitly as a property value. * There is plenty of room still for interpretation, best practice, clearer guidelines; the "How do we identify real world entities" debate is as old as the Web. * Schema.org's deployment in mainstream Web content places some practical constraints for some publishers; for example, a Movie site where a page /person_321/ links to /tvshow-67241/ might have an itemprop="actor" (microdata) or property="actor" (rdfa) annotation. That's nice and simple, but parsing gives the actor TV show the same URI/IRI/URL as the page describing them; i.e. the http-range-14. A more complex site design (markup and identiifers) that gives different IDs to pages and entities is of course possible, but it's not clear we'd see strong adoption easily. So I'd not read too much into 'url'. It's somewhere you can put a Web identifier for the thing being described. As conventions for this in the Web standards community mature, we should be able to be more precise on this. Dan p.s. http://www.w3.org/wiki/WebSchemas/sameThingAs is somewhat related
Received on Tuesday, 23 October 2012 15:26:25 UTC