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Re: Recipe for Shops: Showing up in Yahoo and in the Web of Data in One Turn

From: Martin Hepp (UniBW) <martin.hepp@ebusiness-unibw.org>
Date: Thu, 23 Jul 2009 10:47:04 +0200
Message-ID: <4A682388.7000100@ebusiness-unibw.org>
To: bnowack@semsol.com
CC: semantic-web@w3c.org
Hi Benjamin:

Benjamin Nowack wrote:
> On 22.07.2009 15:32:40, Martin Hepp (UniBW) wrote:
>> Actually, I disagree completely.
>> Conflating multiple resources under one URI is deadly, because it 
>> compromises the later reuse and recombination of data.
> unless there is sufficient overlap as in the vcard example?
Yes, but really see the vCard pattern as the exception from the rule.
In general, statements of equivalence are better kept separate from the 
original data,
because for different usages you will need different sets of mapping 
statements - since semantic alignments are usually approximations only - 
you can have more links with more "false positives" or less links with a 
higher precision.
>> Making the business entity also an instance of vcard:VCard is only 
>> because the upcoming vCard2006 cleansing is not yet available, in which 
>> the domain of vcard:adr is likely to be changed from vcard:VCard to a 
>> wider set of classes, because most locations, persons, or legal entities 
>> can have addresses - not only via a vCard node. (**You** do have an 
>> address, not your business card.).
> Well, that's a pragmatic schema interpretation I agree with. But
> you'll have to be fine with me adding vcard:rev to my gr:Business 
> then, too, which contradicts your statement above.
Well, I cannot stop you from doing so, but I would not use vcard:rev on 
a business entity.
Note that I would rather omit the vcard:Vcard type from the Yahoo 
patterns and plainly attach the vcard:adr to the gr:BusinessEntity. If a 
reasoner infers from that that this is also a vcard:Vcard instance, that 
is a lesser issue, in particular if the domain in the ontology spec will 
change soon, anyway.
But currently the recommended pattern is a Yahoo requirement, afaik.
>> So again, this was only a work-around (initially introduced by Yahoo) to 
>> make the whole thing fly now, not later. 
> Wild agreement. I just wondered if these work-arounds won't 
> automatically become common practice.
Yes, but we should rather limit than recommend them.
Give lay people patterns that work, but don't encourage them to mess up 
conceptual structures.

I agree it is hard to explain the ontological difference between 
gr:ProductOrServiceSomeInstancePlaceholder and gr:ProductOrServiceModel 
to a shop assistant or average Web designer.
But I can say that if you model the datasheet of a commodity for a 
manufacturer, use the latter, and if you are modeling an offer, use the 

And I should tell them not to make a resource an instance of both.

In fact, the GoodRelations validator (currently alpha) at

will tell you if you do.

Note that GoodRelations has now disjointness axioms that simplify 
respective checks.

>> Well, there is nothing I can do about that, it is simply an important 
>> technical requirement.
>> If you omit it, the content will no longer validate and data extraction 
>> and reuse turns from a predictable computational operation into 
>> probabilistic guesswork: it may work, or it may not.
> Is that a Yahoo!ish restriction? AFAIK, the RDFa group has moved 
> away from the DTD requirement, and xmlns can go anywhere.
I did not know that and I also think that reducing the requirements on 
mark-up is more harmful than many proposes think.
As said (not very politely, unfortunately) in

it is as important to train web designers in good mark-up as it is to 
please old browsers.
>> I think that at least such basic RDFa support will soon be a mandatory 
>> feature for any CMS on the market.
> Yes, probably. At least for some time ;) 
What would follow then?
>> Also note that a typical shop etc. may have just a few HTML templates 
>> for e.g. the company and the product detail pages. Ten lines of 
>> additional markup may be worth it if the actual content is generated 
>> automatically from those templates.
> True. I already find the updated example much more attractive.
>> IMO, there is dangerous tendency in part of current Web of Data 
>> research: After the frustration about the complexity (and limited 
>> impact) of logic-centric work, many researchers now want to keep things 
>> deadly simple. 
> Can't say much here, I'm a developer, not a researcher. *I* think 
> there is dangerous tendency in the RDF community to always think 
> about researchers and/or in a researcher-centric way ;) 
Well, I think we are on a good track, but we must keep Albert Einstein's 
comments on the Semantic Web in mind:

"Mke everything as simple as possible, but not simpler."
>> It is not about changing a few lines in an ongoing PhD project ;-). It 
>> would be about changing a running system.
> I guess the only chance to successfully change the schema would be
> right now, but I can't judge if it's worth the hassle. 
Currently, I will not change anything that creates additional effort for 
ongoing adoption.
Changes in the names of existing conceptual elements are things I 
consider such.
Once there are at least 100+ applications out there (likely by the end 
of this year), one can easily introduce a smooth migration with new 
elements or shortcuts linked to established IDs via sameAs, 
rdfs:subProperty or owl:equivalentProperty etc.
> And I'll stop 
> annoying you now. 
You aren't annoying me at all; it is extremely valuable feedback!
> Good luck with the Good Relations, it's clearly a 
> cool effort!
> Cheers,
> Benji

martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

e-mail:  mhepp@computer.org
phone:   +49-(0)89-6004-4217
fax:     +49-(0)89-6004-4620
www:     http://www.unibw.de/ebusiness/ (group)
         http://www.heppnetz.de/ (personal)
skype:   mfhepp 
twitter: mfhepp

Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!


Talk at the Semantic Technology Conference 2009: 
"Semantic Web-based E-Commerce: The GoodRelations Ontology"

Tool for registering your business:

Overview article on Semantic Universe:

Project page and resources for developers:

Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey


Received on Thursday, 23 July 2009 09:10:56 UTC

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