This is the archive of the goodrelations dicussion list

Minor correction:

Problem No. 5:

> 5. Pages may even be banned from search engines ("duplication of  
> content"); that is independent of whether you are using  
> GoodRelations or not.

  is not relevant for Google, at least, see

http://googlewebmastercentral.blogspot.com/2008/09/demystifying-duplicate-content-penalty.html

Best

Martin Hepp


On 24.08.2010, at 15:04, Martin Hepp wrote:

> Dear all:
>
> Some shop applications, unfortunately, display the very same item at  
> multiple URIs. This is problematic for Search Engine Optimization  
> (SEO) and the Web of Data alike.
>
> Examples and Causes
> ===================
>
> There are two typical causes:
>
> a) The navigation path of the shop system is used to create "clean"  
> URIs:
>
>  http://www.myshop.com/staplers/green_pocket_stapler123
>  http://www.myshop.com/featured-items/green_pocket_stapler123
>
> b) Parameters, e.g. such to control the language of the output, the  
> preferred currency, the session ID (bad...), or the referrer.
> This case is more severe, because it can easily cause 10 - 100  
> duplicates per single page:
>
>  http://www.myshop.com/staplers/green_pocket_stapler123
>  http://www.myshop.com/staplers/green_pocket_stapler123?lang=en
>  http://www.myshop.com/staplers/green_pocket_stapler123?currency=usd? 
> lang=en
>  http://www.myshop.com/staplers/green_pocket_stapler123?referrer=clicksale
>
>
> Problems
> ========
> 1. If you embed GoodRelations data markup in RDFa syntax to your  
> HTML/XHTML shop templates, this may cause a massive duplication of  
> data elements for applications that are trying to consume our shop  
> data.
> 2. This will reduce the findability of your items in GoodRelations- 
> aware applications.
> 3. It spoils the Web of Data ("proliferation of URIs").
> 4. Your pages will receive a lower ranking in search engines,  
> because the amount of links will be spread over multiple URIs.
> 5. Pages may even be banned from search engines ("duplication of  
> content"); that is independent of whether you are using  
> GoodRelations or not.
> 6. Crawlers will waste more resources crawling your site, consume  
> more of your valuable bandwidth, and are more likely to use outdated  
> cached versions of your pages.
>
> Solutions
> =========
> 1. The ideal solution is to aim for canonical URIs (one URI per  
> product) as much as possible. This may not be easy for pattern a),  
> but it is straightforward for case b), e.g. by using session cookies  
> and / or HTTP redirects.
>
> 2. If that is not possible, you should use *absolute* instead of  
> *relative* identifiers in RDFa for all major data elements ("about"  
> attribute in RDFa).
>
> For example, in the template for the "product item" page, use
>
> <div about="http://www.myshop.com/staplers/green_pocket_stapler123#offering 
> " typeof="gr:Offering">
> ...
>
> instead of
>
> <div about="#offering" typeof="gr:Offering">
> ...
>
> The effect will be that no matter from which URI the page was  
> actually requested, the same RDF data will be extracted. It  
> requires, though, that you can determine the canonical URI of the  
> page at the time of the request.
>
> 3. The last option (but the least powerful, yet still much better  
> than doing nothing) is to add owl:sameAs statements from the RDFa  
> pattern to the canonical URI.
> The canonical URI should also be used for the foaf:page property,  
> which is the crucial link from the data to the page from where the  
> product can be ordered.
>
> Example:
>
>  <div about="#offering" typeof="gr:Offering">
>    <div rel="owl:sameAs" resource="http://www.myshop.com/staplers/green_pocket_stapler123#offering 
> "></div>
>    <div property="rdfs:label" content="Cool green stapler for $8.99"  
> xml:lang="en"></div>
> ...
>    <div rel="foaf:page" resource="http://www.myshop.com/staplers/green_pocket_stapler123 
> "></div>
>  </div>
> </div>
>
> Best wishes
>
> Martin Hepp
>
>
>
>
> --------------------------------------------------------
> martin hepp
> e-business & web science research group
> universitaet der bundeswehr muenchen
>
> e-mail:  hepp at ebusiness-unibw.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 GoodRelations for E-Commerce on the Web of Linked Data!
> =================================================================
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> * Vocabulary Reference: http://purl.org/goodrelations/v1
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