Re: RDFa and Microformats

Hi Martin,

> I received an un-inspiring response from the RDFa community,  which
> surprised me a little because later that month it was part of the
> Agenda at the following Telecon meeting on the 28th of that month
> http://www.w3.org/2008/08/28-rdfa-minutes.html#item03. I wish I could
> be part of those meetings I would have explained further.

Sorry about that, we're just so swamped that it's hard to keep track of
everything. Also, the W3C process means that our calls have to follow
certain rules. Are you a W3C member by any chance?

> You over complicate microformats if you think of it in that way,  they
> have a very basic parsing model which goes a little something like ....

>From your description (and from our past experience), it already looks
like there are vocabulary-dependent differences. And that's exactly what
we made sure to steer clear of in RDFa.

If you want to use microformats *exactly* as is, you have to vary your
parsing rules based on the microformat in question, and the best way to
do that is, as Toby has mentioned, using GRDDL and @profile. We may
eventually be able to use @profile to feed the RDFa tools pipeline, but
not yet.

What we discussed recently is the possibility of making the prefix story
simpler for microformats-*like* markup, but still using @rel, @property,
@typeof consistently. We still need to work on that, but note that we're
*not* talking about subsuming existing microformats as-is into generic
RDFa, as that would make RDFa parsing vocabulary-dependent. That would
break a lot of the goodness of RDFa.

> You know that's what I always thought, but I have been made to believe
> RDFa is a General Purpose Syntax used to describe semantics in XHTML,
> not limited to just RDF,

That would be incorrect, as RDFa maps directly to RDF. There may be
syntactic sugars for certain URLs and vocabularies, but it's always
triples at the end. What else would it be?

Maybe you're not quite seeing that RDF is powerful enough to express
everything, in particular all microformats. Its power comes from its
generic data model.

> IF RDFa is just about RDF then I will leave you all here and never bring
> up this topic again because it is my view Namespaces/prefixes/CURIEs are
> not that well supported in modern browsers, not even well enough  in the
> W3C's own technologies add that to the fact that anyone can create a RDF
> vocabulary without using any kind of process encouraging website
> developers to build walled gardens around themselves in their own
> namespaces and Vocabularies... UGH! anti-social to say the least.

I think you're conflating and possibly confusing a few issues.

First, there's a mistake: CURIEs need not be explicitly supported in
browsers. We've shown with our implementations [1] that we can easily
build RDFa parsers in existing browsers using simple JavaScript. So
there's no significant question of tool support.

Second, the fact that anyone can create a RDF vocabulary is a feature,
not a bug. The Web is distributed, and there's no reason vocabularies
should be any different. The granularity of individual fields
corresponding to URIs makes for loosely coupled applications that are
vastly more powerful, and the extensibility of vocabularies lets
publishers add value while remaining compatible with existing tools.

Third, walled gardens and anti-social? I think that has nothing to do
with the technology and everything to do with what individual publishers
choose. If they choose to build a walled garden, that's their choice,
but they won't benefit from other tools. There's incentive, in RDFa, to
use existing vocabularies wherever possible, and extend only when
necessary. It's in fact, far more social and collaborative, because you
can benefit from the group while adding your own individual customizations.

Now, is there room in RDFa for simplifying markup in simple cases, by,
for example, declaring a default namespace for an entire DIV? Almost
certainly. But we don't need to break the generic parsing model of RDFa
to get there. The generic parsing model of RDFa is one of its big wins,
in my opinion.

-Ben

[1] http://www.w3.org/2006/07/SWD/RDFa/implementation-report/

Received on Saturday, 13 September 2008 19:06:17 UTC