[Odrl-version2] Microdata and RDFa HTML4/5 specs

Thu Aug 20 00:05:50 EST 2009

Hello Steven Rowat,
Just now a student of us is working to create an ODRL-RDFa-Profile in a thesis. This profile will depend on ODRL version 1.1. The student aims to complete this work until september. Maybe these results can already help you.
Presumbly we will append a thesis of another student in order to extend this to ODRL Version 2.0.

A collegue and I have just taken a look at the features of Microdata. It seems to be comparable to RDFa. RDFa seems to be a little bit more complex, but has a little bit more possibilities. I think learning Microdata will be very easy for someone who already knows RDFa. RDFa has the advantage, that it can be converted very easily to normal RDF (or rather is already RDF), which can be used for other usecases which will not deal with web pages and HTML. But also, Microdata will presumably be easily converted to RDF or other notations.

At this moment, Microdata is not sufficiently established to use it, since it exist just as a draft. Maybe in the long term it will get more support when HTML 5 is completed. So we will continue with RFDa at this moment, but we will have a close eye on the HTML 5 developement.

Sorry, that I cannot say a), b) or c) will be the best way. Nevertheless I hope, I could help you.

Greets, Helge Hundacker

--------------------------
Dipl.-Ing. Helge Hundacker

IT Risk Management
University of Koblenz-Landau, Germany
Phone  +49 261 287-2867
http://www.uni-koblenz.de/~hundacker 

> -----Ursprüngliche Nachricht-----
> Von: odrl-version2-bounces at odrl.net 
> [mailto:odrl-version2-bounces at odrl.net] Im Auftrag von Steven Rowat
> Gesendet: Mittwoch, 19. August 2009 02:03
> An: ODRL-Version2; jeni at jenitennison.com; 
> shelleyp at burningbird.net; ian at hixie.ch; elias at torrez.us; 
> rubys at intertwingly.net; hober0 at gmail.com
> Betreff: [Odrl-version2] Microdata and RDFa HTML4/5 specs
> 
> Greetings,
> 
> Summary of this email:
> 
> In brief, I wish to know what to do about the RDFa/Microdata 
> split: as of today, August 18/09, there appears to be a 
> confusing fork between Microdata and RDFa; and no sign of a 
> resolution; so that html writers, such as myself, will be 
> left wondering which to use. This is particularly troubling 
> after over a decade of hoping for a widely accepted universal 
> metadata standard. So, in the light of repeated calls for 
> use-cases to help decide which of Microdata/RDFa is better 
> and why (see links below), I'm hoping that some progress has 
> been made in this that can be told to me; or, failing that, 
> even that considering my own use-case might be a help, 
> however small, in bringing that decision about.
> 
> Details:
> 
> For the purposes of this email I might describe myself as an 
> 'end-user of extended metadata'. In more common language, I'm 
> designing a complex web site with data that is not easily 
> cataloged by search text-based engines -- audio recordings, 
> graphics, and metaphor-based poems whose themes are not fully 
> or accurately contained in their own literal text. Not only 
> do I wish these things cataloged accurately for 
> software-based searches, I wish them available for DRM 
> (including copyright statements and rights-use prohibitions 
> and permissions, as well as, eventually, prices and protocols 
> for direct sales, through the browser).  These protocols are, 
> for instance, provided by ODRL (the Open Digital Rights 
> Language), which already has draft protocols for both 
> microformats and RDFa implementation (see links on the 
> www.odrl.net page).
> 
> All well and good - then I discovered the new Microdata spec 
> introduced into HTML5 that, according to many observers 
> replaces RDFa, and, according to some observers at least, for 
> no good reason. This was a very confusing discovery. More, 
> when I went further into the web discussions about this 
> replacement I realized it has been the subject of a heavy, 
> active, and ongoing discussion, continuing from May 09, right 
> up into this week in August.
> 
> And today, August 18, Draft HTML5 specs have appeared with 
> today's date -- and only Microdata; no mention of RDFa is 
> found at all in the document (though RDF is mentioned, as one 
> of several protocols Microdata can be exported to.)
> 
> I've put a list below of some of the discussions around this issue. 
> They are extensive, and I'm sure I could find many more.
> 
> So, my question: what's a guy to do? :-) . Or, more 
> importantly, what are the millions of other unique content 
> producers who write html all over the world going to do now?
> 
>     a) Learn RDFa and external vocabularies, like ODRL, for 
> it (and just ignore Microdata...do I need it? Maybe it will go away)?
>     b) Learn to code Microdata, ignoring RDFa (and if so, how 
> do external protocols like ODRL fit with Microdata? Will 
> there be a new ODRL protocol required for Microdata?)
>     c) learn all of Microdata, RDFa, and the external (like 
> ORDL) vocabulary for RDFa, and code my pages so that they 
> have Microdata that calls RDFa that calls the external vocabulary?
>     d) wait and do nothing, and hope either Microdata or RDFa 'wins' 
> on the web? (Note: by my reckoning, it's not just *years* 
> since a widely-accepted extensible metadata protocol was 
> expected on the web; we're into *decades*)
> 
> Any suggestions as to which of these four might be preferable 
> at this time, and why?
> 
> At this point, I'm certainly leaning towards *something* 
> being adopted; it seems like a major, even show-stopper, 
> issue. Although conceivably one that can only be resolved at 
> a different level of the decision-making structure of the web 
> than the one where it is currently stuck.
> 
> 
> Best regards,
> 
> 
> Steven Rowat
> 
> 
> 
> Here are some of the links I investigated about the 
> Microdata/RDFa split:
> 
> Editor's draft 18 August 09 of the HTML 5 Vocabulary:
> http://dev.w3.org/html5/spec/Overview.html#concept-item
> 
> FAQ from the W3C "Frequently Asked Questions (FAQ) about the future of
> XHTML"-- see #6 about extensibility, and #7 especially: "What 
> are W3C's plans for RDFa?"
> http://www.w3.org/2009/06/xhtml-faq.html
> 
> ISSUE-41 Decentralized-extensibility
> http://www.w3.org/html/wg/tracker/issues/41
> 
> Re: Does anyone like microdata? (W3C list). Has defenses for 
> Microdata protocol in HTML5.
> http://lists.w3.org/Archives/Public/public-html/2009Jun/0811.html
> 
> Re: Why bound prefixes are an anti-pattern in language 
> design: (W3 discussion list) 
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/200
9Aug/0075.html
> 
> "Intertwingly" Microdata:
> http://intertwingly.net/blog/2009/05/12/Microdata
> 
> Use Cases and Comparison of RDFa/HTML5 Microdata, Shelley Mon:
> http://realtech.burningbird.net/semantic-web/semantic-web-issu
es-and-practices/use-cases-and-comparison-rdfahtml5-microdata
> 
> What You Can't Do with HTML5 Microdata, Jeni Tennison:
> http://www.jenitennison.com/blog/node/103
> 
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