Sunday, September 08, 2002

Has RDF Failed?

RDF has two problems:
* The first one is that there is no added value in using RDF over plain XML...So these applications don't need a general semantic format, because they have the RSS semantics built-in.
* It's a bit ugly and the purpose of the extra syntax is far from self-explaining, which quickly lead to mistakes in implementations.

"Note that these 2 problems are hardly RSS specific. They will also arise in other attempts to deploy RDF in a community. RDF seems doomed. But I think RDF still has the future, or at least the model of RDF has the future. The problems are in the serialization of RDF."

"So if you design a general format, it is always going to be inferior to a specificly designed format. With RDF this is even worse because RDF can make absolutely no concessions towards semantics...Given all this it is unlikely that RDF as serialized in XML is going to be widely adopted."

I hope RDF is not a failure. His talk of semantic schemas reminds me of the way we use schemas to create and render RDF. By creating schemas that describe how they are to be rendered you get the ability to transform RDF into any bracketed language (HTML, XML, etc). If RDF becomes nothing more than a transport language from one proprietary system to another I think it will have succeeded somewhat. Not using RDF as the primary format of RSS is something that I had expected. It is not necessarily relevant to RDF's long term success. Without it, though, RDF still has to find its first killer application - I expect that's why people are fighting so hard. I would think something in the knowledge management or search engine space (like TAP) but it would take someone like Google to pull it off.

Reading the thread it does have a lot of similarities to the XML Schema debate which began a rebellion. The power of something like Relax NG and HTML is the moments of understanding - of it making sense. With RDF serialized in XML you don't always get that. RDF is flexible enough to get confusing. With HTML, primary schoolers could understand it and use it. Once tools were made, people used them but it was still possible for you to understand and change it when the tools failed. RDF needs at least that ability. Sequences and bags don't help.

It's interesting in that thread that Netscape came close to writing their own RDF database.

I like this quote: "The growling seems to have started with a piece by James “Markup Deity” Clark on an IETF mailing list, in which he states flatly that the IETF shouldn’t settle on XML Schema because (wildly inaccurate paraphrase here) it’s a piece of slack, incomprehensible garbage compared with RELAX NG...Next stop: Clark demystifies RDF serialization. (Hey, I can dream.)" from this blog.

"The claim has been made, offlist, that there was a community consensus to move to namespaces and RDF and modules. If there was such a consensus, now is the time to show where the record of that is. Ken provided a pointer, but it’s not what I asked for, because no one asked "Is it OK if we call this RSS 1.0?"" - said Dave Winer.

There is a semantic web club and by the looks of things an RSS club - everyone gets upset when they're not included. Could you really abandon XML (cause it sucks)? Like web services, the reason is not so much the technology but the acceptance in the developer community - content (and metadata from that content) is still king. Or to put it another way, "Can the common man produce RDF? If the answer is NO which it is, then HOW IN THE FUCK IS RDF EVER GOING TO REACH CRITICAL MASS?".

Most users won't want to read RDF. However, if you're a developer or empowered user, you do. The explosion of HTML tools were due to it being easy for humans to understand and debug (oh and the promise of big dollars). You could look at Frontpage and Dreamweaver's output and decide which was the better tool. Being human readable or decipherable meant that tool writers could debug the programs more readily. This is good stuff don't throw it away. So the goal is to make it as simple and as human readable as possible, given the constraints of XML. It's a cop out to say that you should only use tools; until the machines write the tools that is.

The Burningbird weblog has some counter arguments about using RDF in RSS.
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