7 comments

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  Boris Mann

  9 months ago

  Very cool -- looking forward to talking about this. I have a personal love/hate relationship with microformats that lean mainly toward hate, and I've always suspected that RDFa land had some of the answers. Sounds like we need to bootstrap some example vocabularies?
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  Michael Hausenblas

  9 months ago

  Rob,
  
  Fair criticism re vocabularies. In my experience it is about 80% reuse of existing vocabularies (or ontologies, if you need to impress you boss;) and only in few cases you need to invent terms on your own.
  
  Please have a look at the following URIs and let me know in case you need more:
  
  + http://semanticweb.org/wiki/Onotlogies
  + http://esw.w3.org/topic/VocabularyMarket
  + http://www.schemaweb.info/ (not actively maintained)
  
  Btw, a good way to develop vocabularies and or exchange thoughts would be a VoCamp (http://vocamp.org/wiki/Main_Page).
  
  Cheers,
  Michael
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• 

  roblinton

  9 months ago

  Thanks for those resources Michael, good links.
  
  The vocabulary (or excuse me, ontology ;) that I've put together only adds a few terms so 80/20 theory holds true in our case. These added terms all revolve around describing different kinds of attribution; source, yes, but what nature of source? A copy? Derived work? Inspiration?
  
  A shame to have just missed VoCampOxford. That would have been a wonderful trip.
  
  Cheers,
  
  Rob
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• 

  Manu Sporny

  9 months ago

  Hi Rob,
  
  You do make a couple of fair criticisms:
  
  * The RDFa Syntax Document is complex.
  * We don't go into detail about creating vocabularies.
  * Tools for performing vocabulary document validation are non-existent.
  
  I just wanted to point out that the RDFa Syntax Document isn't meant for everyday web authors - it is meant for people that must have a specification for developing RDFa parsers. If all you want to do is re-use RDFa and you don't want to learn about how it works, the RDFa Syntax Document is not for you.
  
  There is a community site meant to help people learn and understand RDFa, this is where we hope to put the more accessible content about RDFa:
  
  http://rdfa.info/wiki
  
  There are a couple of criticisms that you make, that are not accurate:
  
  * Creative Commons should have re-used Dublin Core.
  * Good RDFa validators/extractors do not exist.
  * There is no way to currently do attribution trails.
  * There needs to be a RDF to human-readable vocabulary conversion tool
  
  There is a very good whitepaper that explains why CCrel was created:
  
  http://cms.communia-project.eu/node/79
  
  In a nutshell, they couldn't just re-use Dublin Core because it didn't have the properties that they needed. Take a look at their vocabulary (which is both machine readable and human readable):
  
  http://creativecommons.org/ns#
  
  Additionally, Creative Commons extended Dublin Core with their own vocabulary terms. This is a major feature in RDFa and the point shouldn't be lost. Creative Commons didn't have to talk to anybody to extend Dublin Core - innovation can happen in a distributed fashion instead of through a centralized standards process. Authoring web vocabularies is something that we haven't focused on yet, but will be detailed on the rdfa.info/wiki site. We had to focus on creating RDFa - the rest will come in time.
  
  There are a couple of RDFa extractors and display programs for Firefox - Operator and Fuzzbot. Support for RDFa will get better in time. In the mean time, you can see a video of Fuzzbot in action here:
  
  http://www.youtube.com/watch?v=oPWNgZ4peuI
  
  You can create the attribution trails that you speak of by using dcterms:source from the Dublin Core Terms vocabulary. I believe it supports your use case:
  
  http://dublincore.org/documents/dcmi-terms/#ter...
  
  Lastly, there does not need to be an RDFa vocabulary validation/display tool for people now that there is RDFa. Note that the Media, Audio, Video, Commerce, and CCrel vocabularies are all marked up using RDFa. This makes them RDF vocabularies that are human and machine readable:
  
  http://purl.org/media/
  http://purl.org/media/audio
  http://purl.org/media/video
  http://purl.org/commerce
  http://creativecommons.org/ns#
  
  Hope this helps - the learning curve for RDFa is steeper than we want it to be right now because there aren't many good tutorials out there. The concepts can be distilled fairly simply but we just haven't gotten much together just yet - we've been busy with creating RDFa. The next year or two will be focused on creating tools for RDFa and teaching it to web authors.
  
  Thanks for your interested in RDFa and blogging about it - I hope some of the information above was helpful.
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• 

  Ben Adida

  8 months ago

  Hi Rob,
  
  I just noticed that your link to the RDFa Primer is to a 1-year-old draft. Have you checked out the latest version:
  
  http://www.w3.org/TR/xhtml-rdfa-primer/
  
  It should be much simpler and easier to understand.
  
  One important issue it does NOT address is the creation of new vocabularies, in part because that's a fairly advanced topic. That said, your feedback on the recent RDFa Primer would be super helpful.
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• 

  roblinton

  8 months ago

  Hi Ben,
  
  Yes, I noticed the newer version, and that vocabularies are no longer mentioned in it. I whole-heartedly agree that vocabularies are an advanced topic and the primer might not be the best place to describe them, but I still think they need an entry point that's a little more accessible than what currently exists.
  
  What I'd *love* to see is something along the lines of what I mention at the end of this post - a set of "gold standard" tools (validators and parsers) that developers can use to let them know that they're on the right track without needing to grok the entire RDFa specification.
  
  I like the primer overall. I think it does a good job of showing the reason for RDFa and then gives just enough information to get a vague idea of the practice. You've no doubt come across this video tutorial which contains about the same level of information:
  http://www.youtube.com/watch?v=ldl0m-5zLz4
  
  But it's easy to digest... Oohh, flashing lights! ;)
  
  I don't think we should underestimate the issue of accessiblity. I see RDFa as reaching out to the "normal" world from the somewhat-airy heights of RDF. It needs to be a welcoming handshake to bring people on board.
  
  Cheers.
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• 

  ithoughts.de

  1 month ago

  Like this blog a lot ... thanks for sharing and giving such high quality links for RDFa.
  reply