[whatwg] Annotating structured data that HTML has no semantics for

Maciej Stachowiak mjs at apple.com
Thu May 14 21:53:23 PDT 2009

On May 14, 2009, at 1:30 PM, Shelley Powers wrote:

> So, if I'm pushing for RDFa, it's not because I want to "win". It's  
> because I have things I want to do now, and I would like to make  
> sure have a reasonable chance of working a couple of years in the  
> future. And yeah, once SVG is in HTML5, and RDFa can work with  
> HTML5, maybe I wouldn't mind giving old HTML a try again. Lord knows  
> I'd like to user ampersands again.

It sounds like your argument comes down to this: you have personally  
invested in RDFa, therefore having a competing technology is bad,  
regardless of the technical merits. I don't mean to parody here - I am  
somewhat sympathetic to this line of argument. Often pragmatic  
concerns mean that an incremental improvement just isn't worth the  
cost of switching (for example HTML vs. XHTML). My personally judgment  
is that we're not past the point of no return on data embedding.  
There's microformats, RDFa, and then dozens of other serializations of  
RDF (some of which you cited). This doesn't seem like a space on the  
verge of picking a single winner, and the players seem willing to  
experiment with different options.

>>> The point is, people in the real world have to use this stuff. It  
>>> helps them if they have one, generally agreed on approach. As it  
>>> is, folks have to contend with both RDFa and microformats, but at  
>>> least we know these have different purposes.
>> From my cursory study, I think microdata could subsume many of the  
>> use cases of both microformats and RDFa. It seems to me that it  
>> avoids much of what microformats advocates find objectionable, and  
>> provides a good basis for new microformats; but at the same time it  
>> seems it can represent a full RDF data model. Thus, I think we have  
>> the potential to get one solution that works for everyone.
>> I'm not 100% sure microdata can really achieve this, but I think  
>> making the attempt is a positive step.
> It can't, don't you see?
> Microdata will only work in HTML5/XHTML5. XHTML 1.1 and yes, 2.0  
> will be around for years, decades. In addition, XHTML5 already  
> supports RDFa.

Supporting XHTML 1.1 has about 0.00000000001% as much value as  
supporting  text/html. XHTML 2.0 is completely irrelevant to the Web,  
and looks on track to remain so. So I don't find this point very  

> Why you think something completely brand new, no vendor support,  
> drummed up in a few hours or a day or so is more robust, and a  
> better option than a mature spec in wide use, well frankly boggles  
> my mind.

I haven't evaluated it enough to know for sure (as I said). I do think  
avoiding CURIEs is extremely valuable from the point of view of sane  
text/html semantics and ease of authoring; and RDF experts seem to  
think it works fine for representing RDF data models. So tentatively,  
I don't see any gaping holes. If you see a technical problem, and not  
just potential competition for the technology you've invested in, then  
you should definitely cite it.

> I am impressed with your belief in HTML5.
> But
>> One other detail that it seems not many people have picked up on  
>> yet is that microdata proposes a DOM API to extract microdata-based  
>> info from a live document on the client side. In my opinion this is  
>> huge and has the potential to greatly increase author interest in  
>> semantic markup.
> Not really. Can do this now with RDFa in XHTML. And I don't need any  
> new DOM to do it.
> The power of semantic markup isn't really seen until you take that  
> markup data _outside_ the document. And merge that data with data  
> from other documents. Google rich snippets. Yahoo searchmonkey.  
> Heck, even an application that manages the data from different  
> subsites of one domain.

I respectfully disagree. An API to do things client-side that doesn't  
require an external library is extremely powerful, because it lets  
content authors easily make use of the very same semantic markup that  
they are vending for third parties, so they have more incentive to use  
it and get it right.

>> Now, it may be that microdata will ultimately fail, either because  
>> it is outcompeted by RDFa, or because not enough people care about  
>> semantic markup, or whatever. But at least for now, I don't see a  
>> reason to strangle it in the cradle.
> Outcompeted...wow, what a way to think of it. Sorry, but competition  
> has no place in spec work.

With due respect, you're the one who brought competition into this  
discussion by saying there can only be one winner. I don't really  
think that's true, in this case.


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