So how about using RDFa in Microformats?

Yes, I know...everyone seems to think that RDFa and Microformats are at war. And maybe some would prefer it to be that way. But whatever way you look at it, the work of the Microformats community has been key in getting people fired up about what they might do with metadata that is placed in HTML and XHTML pages. And RDFa is benefiting from the vibrant atmosphere which they have created.

That doesn't mean I'm saying we can ignore the problems and limitations that Microformats have, such as the difficulty in mixing different formats in one document, the work involved in creating new formats (often wastefully duplicating work that has already been done, since specialist formats invariably already exist), or perhaps most significantly, the inability to refer to things that are not 'the current document'.

So I have a suggestion.

Why don't we emphasise the 'micro' in Microformats?

Emphasise the 'micro'

One of the original motivations for Microformats was that they were small, self-contained sets of rules that authors could apply to their documents, which would give the author some kind of benefit. Nothing in that broad definition says 'so therefore steer clear of all other formats or you'll catch the plague'.

So why not use RDFa features within microformats, as appropriate? But Microformats could still retain the compactness of a particular format.

I'll use rel-license as an example.

rel-license

The rel-license microformat is simply the use of the value "license" in the @rel attribute, in some mark-up. For example, if we want to say that the current document is licensed under one of the Creative Commons licenses, we might use the following mark-up in our document:

<a rel="license" href="http://creativecommons.org/licenses/by/2.0/">cc by 2.0</a>

However, what if we have a search page that returns lots of images or videos? What if each image or video is available under a different license to other images or videos on the page, or to the license for the page itself? Trying to solve this problem within the framework set by Microformats is proving quite difficult (see the open issues on the rel-license issues page), so at some point we need something more than rel-license.

Reusing @src attribute

The mark-up we gave earlier to indicate that 'this document' is available under a certain license, amounts to two attributes, @rel and href:

<a rel="license" href="http://creativecommons.org/licenses/by/2.0/">cc by 2.0</a>

RDFa lets us take that little 'package' (or 'microformat') and use it anywhere that we can set a 'subject'. Of course normally the subject is the current document, which is why the rel-license microformat looks just the same to an RDFa parser as it does to a Microformats parser. But RDFa allows this 'package' to be used with the @src attribute, giving us the following possibilities:

<img src="my-picture.png" rel="license" href="http://creativecommons.org/licenses/by/2.0/" />

<object src="my-video.mov" rel="license" href="http://creativecommons.org/licenses/by/2.0/" /></object>

As you can see, this straightforwardly solves the problem that rel-license is presenting to those who want to put many items in a page, so all that would be required to take this solution into the Microformats world would be to slightly extend the rel-license microformat to allow the src attribute as a subject.

RDFa or Microformats?

This example illustrates that if we see RDFa and Microformats as playing slightly different roles, then there is no need to take an 'either/or' approach to the two techniques.

Since RDFa is a general-purpose syntax that is capable of supporting any vocabulary that anyone comes up with, now or in the future, then we are often tempted to talk about the general rules. But for new users who are looking to achieve a specific goal, seeing documentation about a specific usage pattern (such as the one I've shown here with licensing), will almost certainly be more useful to begin with.

But that is what Microformats is all about--documenting common usage patterns in such a way that people can re-use them in their own mark-up. So what would be wrong with enhancing rel-license to allow the use of @src?

Note that people wanting to parse this microformat could either create a specific parser in the way that they need to do now for other microformats, or they could use a general-purpose RDFa parser.

The key thing is that the mark-up is exactly the same, whether you arrived at the use of @rel="license" via the Microformats page, or an RDFa page.

And that seems to me to be a good result all round, for the authors, for the programmers, for the search engines, and especially for those of us who want to see a more dynamic, usable, and semantic, web.