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Re: Indicating main entity / primaryTopic - proposal to use 'schema.org/about'

From: <martin.hepp@ebusiness-unibw.org>
Date: Wed, 6 Aug 2014 01:48:16 +0200
Cc: Dan Brickley <danbri@google.com>, Dan Scott <dan@coffeecode.net>, Jocelyn Fournier <jocelyn.fournier@gmail.com>, W3C Web Schemas Task Force <public-vocabs@w3.org>
Message-Id: <11755FB7-C3B4-47B4-A9AF-7F7EFB617254@ebusiness-unibw.org>
To: Jarno van Driel <jarnovandriel@gmail.com>
On 05 Aug 2014, at 22:52, Jarno van Driel <jarnovandriel@gmail.com> wrote:

> To revive the subject of this thread I have made some markup examples (microdata).
> 
> The first example illustrates what could happen if we add a new property like 'mainEntity' as opposed to expanding the range of 'mainContentOfPage' to Thing:
> 
> https://www.w3.org/wiki/WebSchemas/ChainingLayoutElements#A_CollectionPage_which_has_an_ItemList_as_it.27s_mainEntity_.28down_the_DOM.2C_normal_relation.29_2
> 
> While the next two examples illustrate, that if the markup is less elaborate, explaining the difference when to use mainContentOfPage or mainEntity start to become difficult:
> 
> https://www.w3.org/wiki/WebSchemas/ChainingLayoutElements#A_CollectionPage_which_has_an_ItemList_as_it.27s_mainContentOfPage_.28down_the_DOM.2C_normal_relation.29
> 
> https://www.w3.org/wiki/WebSchemas/ChainingLayoutElements#A_CollectionPage_which_has_an_ItemList_as_it.27s_mainEntity_.28down_the_DOM.2C_normal_relation.29
> 
> Yet if we expand the range of 'mainContentOfPage' to Thing we could get something like this:
> https://www.w3.org/wiki/WebSchemas/ChainingLayoutElements#CollectionPage.2C_ItemList.2C_Product
> 
> Looking at this I think I'd prefer to expand the range of 'mainContentOfPage' to Thing as opposed to adding 'mainEntity'. Solely because a lot less markup is needed.
> 
> Any thoughts?
> 
+1 for expanding the range of 'mainContentOfPage' to Thing.
Equally important to fixing this in schema.org would be proper support in Google, i.e. that the most appropriate Rich Snippet type will be selected based in mainContentOfPage despite the presence of other entitites in the page.

Martin

> 
> 
> 
> 2014-06-02 21:20 GMT+02:00 Jarno van Driel <jarnovandriel@gmail.com>:
> Besides the naming of the property I was wondering what to do when the main entity isn't a single thing but a collection of things. For example a category page (CollectionPage) of an eCommerce site which shows a collection of products?
> 
> In this case there is no main entity unless it's the predicate for a Collection entity. (Maybe something as described in the Collection proposal - http://www.w3.org/wiki/WebSchemas/Collection).
> 
> When I combine the 2 I can imagine marking up something like this:
> 
> <body vocab="http://schema.org/" typeof="CollectionPage">
>   <header property="hasPart" typeof="WPHeader">...</header>
> 
>   <main property="mainEntity" typeof="Collection">
>     <ul>
>       <li property="hasPart" typeof="Product">...</li>
>       <li property="hasPart" typeof="Product">...</li>
>       ...
>     </ul>
>   </main>
> 
>   <aside property="hasPart" typeof="WPSideBar">...</aside>
> </body>
> 
> Or would it be OK to add a property like @mainEntity first and work on the collection issue separately?
> 
> Jarno van Driel
> Technical & Semantic SEO Consultant
> 8 Digits - Digital Marketing Technologies
> 
> 
> 2014-05-21 22:59 GMT+02:00 Jarno van Driel <jarnovandriel@gmail.com>:
> 
> What I think we want is a property that performs the same role as FOAF's 'primaryTopic': it should point to at most one entity/thing. Given currently popular terminology we might call it 'mainEntity' as a
> strawman.
> 
> Couldn't changing the expected value of @mainContantOfPage to Thing work for this?
> 
> Doing so would actually help a lot of websites. I've lost count how many times I've encountered:
> <div itemprop="mainContentOfPage" itemscope itemtype="http://schema.org/Product"> (or Article or Blog). 
> 
> And by expanding the domain of @mainContentOfPage all those websites would automagically have valid markup.
> 
> 
> 2014-05-21 21:22 GMT+02:00 Dan Brickley <danbri@google.com>:
> 
> On 21 May 2014 19:21, Dan Scott <dan@coffeecode.net> wrote:
> > On Wed, May 21, 2014 at 02:04:20PM +0200, Jarno van Driel wrote:
> >>
> >> I was wondering, can an entity also have multiple @about properties?
> 
> That's the right question to be asking. And I didn't ask it hard
> enough yesterday (probably because I wouldn't have liked the answer).
> 
> The wording http://schema.org/about has currently, "The subject matter
> of the content." is awkward. The word "the" suggests a single thing is
> the subject matter, but it is vague enough that you could have several
> entities via repeated properties together capturing "the subject
> matter".
> 
> What I think we want is a property that performs the same role as
> FOAF's 'primaryTopic': it should point to at most one entity/thing.
> Given currently popular terminology we might call it 'mainEntity' as a
> strawman.
> 
> I was hoping we could get away with refining the interpretation of
> 'about', but I'm coming around to the view that it has been used in
> too many diverse ways over the last 3 years for that to work.
> 
> >> I ask because when chaining multiple entities to a WebPageElement, to me
> >> it
> >> seems the following is the logical thing to do:
> >>
> >> <body itemscope itemtype="http://schema.org/WebPage">
> >>    ...
> >>    <div itemprop="hasPart" itemscope
> >> itemtype="http://schema.org/WPSideBar">
> >>        <div itemprop="about" itemscope
> >> itemtype="http://schema.org/ContactPoint">...</div>
> >>        <div itemprop="about" itemscope
> >> itemtype="http://schema.org/ItemList">...</div>
> >>    </div>
> >>    ...
> >> </body>
> >>
> >> Or would @hasPart or @mentions be prefered over @about?
> 
> I don't think they're great examples of about-ness, except
> ContactPoint, if the page is indeed about contact info. The
> stereotypical use for 'about' is a specific person-place-or-thing that
> the content is 'about'. Sidebars and lists are structural mechanisms;
> it would be more typical to see Product, Book, Person, Place etc used.
> However your main point, that 'about' could credibly be repeated given
> its definition, is quite reasonable.
> 
> >
> > I'm not going to offer any advice about whether "hasPart" or "mentions"
> > might be preferred here, but you can certainly have multiple "about"
> > properties for a single entity.
> 
> Yeah. It is tempting to defend a strict reading of the word 'the' and
> claim it shouldn't _really_ be repeated; but I don't think that's
> credible.
> 
> > See the example for http://schema.org/MedicalScholarlyArticle - "about"
> > is used twice, because the article is about a type of drug and
> > about a type of medical condition.
> 
> quite :)
> 
> 
> > The cardinality of schema.org properties appears to be a FAQ dating back
> > to at least 2011 (http://www.w3.org/2011/webschema/track/issues/5); we
> > should probably add an explicit statement to
> > http://schema.org/docs/gs.html or http://schema.org/docs/faq.html (or
> > both) saying that you can, in general, repeat properties in schema.org
> > entities as necessary.
> 
> There are a few (e.g. birthDate, deathDate, most boolean-valued
> properties) that have at most one sensible value. However even those
> might have several reasonable encodings. And there are some, e.g.
> iataCode hopefully, for which there should be at most one entity that
> has any given value for that property. However we've not attempted
> cataloguing these cases, partly through a concern to avoid making
> unrealistically brittle and rigid rules that will be ignored...
> 
> cheers,
> 
> Dan
> 
> 
> 
Received on Tuesday, 5 August 2014 23:48:46 UTC

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