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Re: Discussion with Ian and Henri about HTML5+RDFa (part 2/2)

From: Philip Taylor <pjt47@cam.ac.uk>
Date: Tue, 27 Jan 2009 17:54:26 +0000
Message-ID: <497F4A52.8090102@cam.ac.uk>
To: Ben Adida <ben@adida.net>
CC: public-rdf-in-xhtml-tf@w3.org, Dan Brickley <danbri@danbri.org>, Manu Sporny <msporny@digitalbazaar.com>, Ian Hickson <ian@hixie.ch>, Henri Sivonen <hsivonen@iki.fi>, Sam Ruby <rubys@intertwingly.net>

Ben Adida wrote:
> Philip Taylor wrote:
>> I don't have any decent statistics, but I've got some quick
>> hacked-together data at http://philip.html5.org/data/cc-errors.txt
>> [...]
> Hi Philip,
> Thanks for this info. I think you're talking about RDF in comments, the
> ugly old style we had, and the central reason we worked on RDFa :)

Ah, good point! I got them a bit mixed up. Anyway, it's good to see that 
there were problems with the RDF-in-comments syntax that have been 
avoided now :-)

> CC's new recommendation, since last summer, is to use RDFa such as:
> [...]
> Note how this no longer includes the license details (just de-reference
> the license URL for that), so we expect this to be much more robust than
> the RDF in comments you analyzed.

"last summer" is a bit recent and my data is currently about a year old, 
but I still found 4 examples of that RDFa syntax, listed at 

The markup in each case is different enough that it looks like people 
are editing these things by hand, not simply copying the untweaked 
output of a tool.

One of those uses <a href="www.invaligia.com" 
property="cc:attributionName" rel="cc:attributionURL"> which means it's 
talking about the nonexistent page 

Two are not well-formed XML within the Creative Commons block of markup; 
the other two are not well-formed XML in the rest of the page. So it's 
not possible to extract the RDFa with an XML parser -- you would have to 
use an HTML parser instead (and presumably add hacks to emulate XML 
Namespace processing).

Somewhat relatedly, there's another four pages that use rel="dc:type". 
One of those (http://bytestrike.blogspot.com/) has it near a CC license 
link and does not have an xmlns:dc declaration anywhere, suggesting a 
copy-and-paste error.

I should probably try downloading some more recent pages, to see if 
CC/RDFa usage is more common now...

Philip Taylor
Received on Tuesday, 27 January 2009 17:55:02 UTC

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