People interested in semantic web and linked data developments are all talking about the recent Google (along with Yahoo! and Bing) announcement of schema.org, their solution to semantically marking up pages to improve the display of search results. They propose microdata which is still a work-in-progress from the W3C. No real reason is given for this choice and they vaguely state that "while the long term goal is to support a wider range of formats, the initial focus is on Microdata." As a relative newcomer to implementing linked data using Drupal (we're actually still in early days), I immediately tried to sort out what the schema.org announcement means for Drupal, especially for those, like me, who are, in the words of the title of Stéphane (scor) Corlosquet's master's thesis, hoping to "bootstrap the web of data" with my Drupal site.
For about 6 months now, I've followed Scor's work on getting many of the semantic web and linked data components into Drupal and now, with Drupal 7, into core, along with Lin Clark and others who have done a fantastic job of leveraging Drupal's framework in a/for a semantic web context. Lin has some great videos on her site and YouTube channel and Scor's master's thesis is a great read (oh, what a geek I've become!). No, really, it is fascinating to watch all these moving parts come together in a Drupal.
So, when the schema.org announcement was made, I was glad to see this discussion thread materialize in the Semantic Web group on drupal.org. And, sure enough, Lin and Scor offer their take on this development. Lin focuses on the more positive aspect of these developments noting that Michael Hausenblas and Richard Cyganiak have already created http://schema.rdfs.org/ and she points out that:
I have started a project to ensure compatibility between Microdata and RDFa + the RDF Mapping API as much as possible... and I think that a good integration is possible. I don't see this as a threat at all, I believe that this is a great step in getting people more interested in this technology.
She then goes on to reference Clay Shirk's paper on "evolvable systems" and see this development as an incremental step forward for web of data deployment and adoption. From my limited knowledge so far of how all these bits fit together in a Drupal context, I would agree with her completely.
Scor is a bit more cautious/suspicious in his comments. He applauds the major search engines for their initiative in collaborating on schema.org but wonders why the exclusivity of the microdata choice. He's correct, Google does say here that the continued use of other syntaxes, namely microformats and RDFa, is fine but just don't mix them with microdata or it will "confuse their parsers." Scor responds with regard to RDFa and microdata:
Both of these syntaxes do not share any attribute in common, I'd like to understand where this argument is coming from... as if they don't have the skills to write parsers, or are they just too lazy to bother with RDFa?
Scor goes on to note that schema.org is expecting everyone to adopt a standard not yet in use (microdata) and likens this lack of consensus-building to the fact that the "HTML5 spec has one editor and he's a Google employee".
What I'm trying to sort out, again, with my "newbie" knowledge of all of this in a Drupal context, is what to make of the real implications. The schema.org site has information on extending their vocabulary. They seem to be (attempting, anyway) to follow Allemang and Hendler's (Semantic Web for the working ontologist) and W3C AAA principal - Anyone can say Anything about Anything. So, schema.org's notes that:
Many applications, including search, can make use of structured data only when it’s expressed using vocabularies that they understand. However, the variety and richness of structured data covering everything on the web is much too rich for a single organization (like schema.org) to completely cover.
But, as David Wood points out in his post on the announcement, this could be a further attempt by Microsoft (now with Google in tow) to combat RDF and semantic web adoption where they see these threatening their business model(s). Time will only tell if they will succeed, he notes. And, this Manu Sporny post brings all of the criticism together into a rather frightening chain of events that have led to Schema.org.
However, as we're actively using Drupal 7 to markup our data in order to connect to the web of data, I'm most concerned about compatibility and the work Lin refers to that will, hopefully, bring all of this together. In all honesty, I'm a busy web manager (100+ websites in Drupal) that just happens to come from a library and info science background and have a "research" interest (and, personal interest) in semantic web and web of data/linked data. So, I'm following these developments and care about the outcome, especially in the context of the Sporny post above. But, many web development managers and webmasters simply don't have time to "care" and will follow the schema.org lead on this.
For now, I guess I'll follow projects like the Microdata support in core, this thread in the Semantic Web Drupal group, which has been updated with 2 new comments just since I started writing this post!, the schema.rdfs.org site, which lists tools for utilising the mapping of schema.org to RDF, and carry on. As a relative newcomer to many of the issues I've just written about above, I would appreciate any comments or clarifications on the issues above, to correct any misconceptions or inaccuracies. Many thanks!