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

[Maciej Stachowiak]

On May 18, 2009, at 6:05 AM, Eduard Pascual wrote:

> On Mon, May 18, 2009 at 10:38 AM, Henri Sivonen <hsivonen at iki.fi>  
> wrote:
>> On May 14, 2009, at 23:52, Eduard Pascual wrote:
>>
>>> On Thu, May 14, 2009 at 3:54 PM, Philip Taylor <excors+whatwg at gmail.com 
>>> >
>>> wrote:
>>> It doesn't matter one syntax or another. But if a syntax already
>>> exists (RDFa), building a new syntax should be properly justified.
>>
>> It was at the start of this thread:
>> http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2009-May/019681.html
> Ian's initial message goes step by step through the creation of this
> new syntax; but does *not* mention at all *why* it was being created
> on the first place. The insight into the choices taken is indeed a
> good think, and I thank Ian for it; but he omitted to provide insight
> into the first choice taken: discarding the multiple options already
> available (not only Microformats and RDFa, but also other less
> discussed ones such as eRDF, EASE, etc).


I think Ian did explain why he discarded RDFa as an option.

In the email linked above, Ian Hickson wrote:
> Another solution we could consider is RDFa:
>
>      <section typeof="d:cat" xmlns:d="http://damowmow.com/">
>       <h1 property="d:name">Hedral</h1>
>       <p property="d:desc">Hedral is a male american domestic  
> shorthair,
>       with a fluffy black fur with white paws and belly.</p>
>       <img src="hedral.jpeg" alt="" title="Hedral, age 18 months"
>       class="photo" rel="d:img">
>      </section>
>
> This unfortunately also has a number of problems.
>
>  - it uses prefixes, which most authors simply do not understand, and
>    which many implementors end up getting wrong (e.g. SearchMonkey
>    hard-coded certain prefixes in its first implementation, Google's
>    handling of RDF blocks for license declarations is all done with
>    regular expressions instead of actually parsing the namespaces,  
> etc).
>    Even if implemented right, namespaces still lead to flaky
>    copy-and-paste behaviour.
>
>  - it sometimes uses rel="" and sometimes uses property="" and it's  
> hard
>    to know when to use one or the other.
>
>  - it introduces much more power than is necessary to solve this  
> problem.


I believe Microformats were discarded as a solution because the  
proposed use case was as follows:

> USE CASE: Annotate structured data that HTML has no semantics for,  
> and which nobody has annotated before, and may never again, for  
> private use or use in a small self-contained community.

But Microformats are only intended for widely used and generally  
agreed upon public vocabularies. The Microformats process is not  
applicable to private-use/small-community vocabularies. And  
Microformats define specific vocabularies, not a general way to add  
new kinds of semantic markup. I expect Microformats experts would  
agree with this assessment.


So I think it is clear why neither Microformats or RDFa were seen as  
suitable solutions to the use case, even if the matter was addressed  
somewhat briefly.


Regards,
Maciej