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Re: Yahoo's RDF vocabularies

From: Peter Mika <pmika@yahoo-inc.com>
Date: Thu, 19 Mar 2009 16:48:53 +0100
Message-ID: <49C26965.7010307@yahoo-inc.com>
To: Manu Sporny <msporny@digitalbazaar.com>
CC: RDFa <public-rdf-in-xhtml-tf@w3.org>, "public-rdfa@w3.org" <public-rdfa@w3.org>
Hi Manu,

> SearchMonkey outlines what people must do to get their video listings in
> Yahoo's search service using the Yahoo Media vocabulary. So while you
> can write your own SearchMonkey apps using your own vocabularies, you
> can (right now) only use Yahoo's vocabulary if you want the enhanced
> search listings to show up on the main Yahoo search page, right? This
> sends a pretty strong message - use Yahoo's vocabularies or you won't
> show up in the enhanced listings.
> What's the timeline for allowing other vocabularies to be used for
> indexing purposes for the main search page listings?
It's again important to clarify that that is not the case. You can use 
any RDFa vocabulary and build a SearchMonkey application that acts on 
data formatted according to that vocabulary.

> Taking something that already exists for syndication purposes and
> transforming it into an RDF vocabulary on a 1-to-1 basis is not a best
> practice because the syndication format makes some very strong
> assumptions about the data in the stream. RSS data is fairly strongly
> typed data, and is machine generated in a controlled environment. RDFa
> data is usually not strongly typed, is generated by humans as well as
> machines, and is not in a very controlled environment.
I'm not sure I follow you on this distinction... what do you mean by RSS 
is 'fairly strongly typed' data while RDFa is not? RDFa has explicit 
typing, just like XML Schema.
> MediaRSS also contains both elements /and/ attributes to refine the
> meaning of the elements. However, it seems that only the elements made
> it over to ymedia, which is unfortunate because a great deal of semantic
> fidelity is lost without the attributes.
I'm not sure I understand what you are referring to. In this case width 
and height are attributes in XML, and properties in RDF.
> Also, the vocabulary specifies both ymedia:title /and/ suggests the use
> of dc:title. There is no need for ymedia:title since you're just
> re-defining what dc:title already does. There is an argument for helping
> web authors by only requiring them to include one vocabulary, but it is
> at the expense of teaching people that it's okay to re-create entire
> vocabularies under that argument - which is detrimental to all of this
> in the long run.
> I think the solution would be something along the lines of @profile
> pre-loading a set of vocabularies, so Yahoo could use multiple
> vocabularies in a stack without creating undue burden on the HTML author:
> <html profile="http://search.yahoo.com/searchmonkey-vocabs.html">
> ... <span property="dc:title">Puppies</span> ...
>   ... <span property="format:width" content="1080">HD</span> ..
This would be incompatible with RDFa, no?

>> We do publish OWL definitions for the vocabularies at [2].
> Good! But that's so 2007! :)
> Why not mark up the same pages that define the human readable vocabulary
> with a machine readable one using RDFa, like these pages do:
> http://purl.org/media/
> http://purl.org/media/audio
> http://purl.org/media/video
> http://purl.org/commerce/
No one has ever requested it until now ;) Why is it better than a 
separate OWL document? OWL is very 2009 ;) 
> Hmm, maybe... I thought the general sense on the web was that schema
> versioning was a bad idea and should not be done. If you really need to
> shift versions, you can always point people at a new URL and clearly
> mark the old URL as deprecated, as the Dublin Core folks did.
I'm not sure if the world is ready for that...
>> The only non-issue I see from
>> your list of comments is the issue of prefixes: we have URIs in RDF(a)
>> and there already plenty of namespace clashes in the sense you describe:
>> RDF Calendar and Dublin Core both have at least two namespaces.
> Right, which is why I pointed out RDFa's resiliency in the previous
> e-mail... but it still does create a rather large problem for these
> types of proposals, so I don't think it is a non-issue... just one that
> we may be able to begrudgingly live with:
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2009Mar/0037.html

> Hope to keep working through the issues and providing feedback. Thanks
> for replying and reading through this rather long set of thoughts :)
> -- manu
I'm happy to respond. We should probably try to avoid using this mailing 
list for discussions about specific vocabularies. In particular, based 
on evidence all over the Web, discussions are media vocabularies tend to 
be lengthy and most likely uninteresting for anyone on this list who is 
not working with media content.

Received on Thursday, 19 March 2009 15:50:01 UTC

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