Tuesday, August 09, 2005
The sad thing is that while namespaces theoretically addressed one of the problems I pointed out (calling different things by the same name), it actually WORSENED the other problem: calling the same thing by different names. XML Namespaces encouraged document/data silos, with little or no reuse, probably because every person/political body defining their elements wanted "control" over the definition of any particular thing in their documents. The <svg:a> tag is the perfect example of needless duplication.
And if something was theoretically supposed to have solved something but effectively hasn't 6-7 years later, then in our internet-time-frame, it has failed.
This is a valid problem in the real world. For example, for all intents an purposes an <atom:entry> element in an Atom feed is semantically equivalent to an <item> element in an RSS feed to every feed reader that supports both. However we have two names for what is effectively the same thing as far as an aggregator developer or end user is concerned.
The XML solution to this problem has been that it is OK to have myriad formats as long as we have technologies for performing syntactic translations between XML vocabularies such as XSLT. The RDF solution is for us to agree on the semantics of the data in the format (i.e. a canonical data model for that problem space) in which case alternative syntaxes are fine and we performs translations using RDF-based mapping technologies like DAML+OIL or OWL. The microformat solution which Tantek espouses is that we all agree on a canonical data model and a canonical syntax (typically some subset of [X]HTML).
So far the approach that has gotten the most traction in the real world is XML. From my perspective, the reason for this is obvious; it doesn't require that everyone has to agree on a single data model or a single format for that problem space.
Microformats don't solve the problem of different entities coming up with the different names for the same concept. Instead its proponents are ignoring the reasons why the problem exists in the first place and then offering microformats as a panacea when they are not.