RDFa

We’ve reached a point where new editors’ drafts of the syntax and processing document, and an introductory primer are available, ready to be reviewed by the W3C’s Semantic Web Deployment Group at their next face-to-face meeting.

Take a look. RDFa is pretty close to completion…and now the fun can really begin.

Kurt Cagle has a stunning article on RDFa, and interestingly enough draws attention to CURIEs as a key technology, since it formalises the use of scoped vocabularies.

I could draw attention to many interesting points, but one that particularly caught my eye was:

RDFa and Atom make for a surprisingly potent combination. One provides a useful way for annotating XHTML content with metadata easily and unobtrusively. The other provides a way of transporting both the metadata and its corresponding links such that generalized feed processors can display at least a minimal set of information about the given resource, and specialized feed processors can take the same Atom feed and use the object properties to generate considerably more sophisticated effects.

An excellent observation.

For anyone not familiar with Kurt’s work, it’s great to see him writing about RDFa. Kurt has a knack for being able to see the long term potential of new technologies, but at the same time explain to would-be users why such technologies could be useful to them.

He goes on:

Look for an upcoming article that will delve into the formal mechanics of building Atom feeds from RDFa and illustrating how you can extend certain CMS systems to better incorporate RDFa as a core capability.

I for one, am looking forward to that, and I think a lot of people will find those articles incredibly useful.

Fresh from the Semantic Web Activity News: GRDDL is a W3C Recommendation.

As you might know, GRDDL can also be used to generate RDF from XHTML+RDFa documents. However, there are people around preferring to use RDFa rather directly

There’s an interesting discussion going on over at xml-dev about how to mark-up documents that will still need to be around in 20 years time, such as legal documents or financial transactions. A number of ideas have come up, and interestingly one of them is to use RDFa. Now that the RDFa specifications are pretty much complete we’ll soon be able to get involved in these kinds of discussions, and explain how RDFa can provide a solution–indeed it was designed to.

Just a bit ago, Sandro Hawke announced the launch of the new OWL Working Group (aka OWL 1.1):

W3C is pleased to announce the launch of the OWL Working Group. Ian Horrocks (Oxford University) and Alan Ruttenberg (ScienceCommons) chair the group which is chartered to produce a W3C Recommendation for an extended Web Ontology Language (OWL), adding a small set of extensions and defining profiles identified by users and tool implementers.

I’m looking forward seeing how this evolves …

Ivan Herman has announced a new Python-based RDFa implementation in his blog. The Python package is available online.

Ivan has also interfaced it to a Web page that takes the URL of an RDFa page and extracts the RDF in a choice of outputs.

Peter Krantz has some extremely interesting thoughts on the use of RDFa in assistive technologies. It makes thought-provoking reading not just because it raises some interesting ideas about accessibility, but also because it gets us thinking about how we might define a processing model that sits on top of RDFa, that would in turn allow all sorts of functionality. Peter gives an example at the end of his article:

In practice, the sequence of events for a screen reader working on top of a web browser could look like this:

1. Browser opens the web page.
2. Screen reader parses the HTML and extracts references to all external vocabularies.
3. External vocabularies are fetched and parsed for labels and descriptions.
4. The screen reader announce that extended information exists and starts rendering the page.

So, by using RDFa to reduce ambiguity for machines it is likely that humans too can benefit from the added information. It will be very interesting to see what makers of assistive tools can come up with.

Gauthier Poupeau continues his work on exploring what one can do with Operator and RDFa. He now has an Operator action script that look for ISBN numbers expressed as RDFa, then links them to Amazon. He has another Operator action script that gives you a URL’s history at delicious. It’s all described in detail in French on his blog.

All of these small client-side hacks are the beginning of the most important part of the whole semantic web story: giving the user power to do things according to the semantic markup. There’s so much promise here, it’s exciting to see RDFa providing a solid basis for this kind of innovation.