- From: Dan Brickley <danbri@w3.org>
- Date: Fri, 17 Dec 2004 20:44:48 -0500
- To: Brian Manley <manleyr@telcordia.com>
- Cc: Frank Manola <fmanola@acm.org>, www-rdf-interest@w3.org
Hi Brian, * Brian Manley <manleyr@telcordia.com> [2004-12-17 17:44-0500] > > Hi Frank, > > "how do you define a 'non semantic web application'" > > This is a hard question. I think I know a semweb app when I see it, > but I'm not sure how to define it. I think ( perhaps naively ) > of semweb applications as those that either produce or consume RDF > metadata relating to web-accessible resources. RSS aggregators, > browsers, etc. fall into this category. On the other hand, a non > semweb application doesn't really concern itself with whether or > not the resource it's describing is a web-accessible resource or > not. It could be a web page about rocks, or an actual, physical rock. I don't find this a helpful way to draw the distinction. Sorry! Guess that means I need to sketch an alternative. Hmm. Let me try. The phrase "Semantic Web" is a slogan for our efforts to make Web-based systems more sensitive to some aspects of the meaning of documents. In particular, about what those documents tell us about various kinds of relationships between all kinds of thing, offline and on. eg. documents are made by people, and describe people, places and ideas etc. All metadata efforts, whether labeled "Semantic Web" or not, have grappled with this. The Resource Description Framework is a piece of W3C technology designed to progress the Semantic Web project, by providing a domain-neutral set of conventions for describing things (whether people, documents, events, places, whatever...) in terms of named relationships. RDF, even before we started using the phrase "Semantic Web", is *always* happy mixing descriptions of online/electronic and offline/realworld things. In many ways, that was the point. Before RDF, metadata initiatives tended to get started with a particular kind of thing or topic area as their central focus. This was great, except it meant that we ended up with people working on file formats, XML/SGML tagsets etc each oriented towards "Education" or "Images" or "Rights", or "Computer Science Reports" or "Software" or "Mapping/Location". RDF was created through W3C's Metadata Activity as an acknowledgement that these different forms of metadata were describing a common, rich, highly linked world, and that mixing them together was a recognised need in the metadata community (eg. see the Warwick Framework efforts associated with the Dublin Core community). Time passed, and the slogan "Semantic Web" got deployed, in part because the concept of "metadata" is a tricky thing to define, and "data about data" doesn't quite work when you look at the details. Often your "data about data" turns out to be "data about real world entities associated with your data", eg. the location of a photo, or the contact info for an author, or the price of something. It was also an acknowledgement that the RDF design was very general purpose, and applicable to fairly arbitrary data interchange, rather than the application areas traditionally associated with the label "metadata". So, RDF is a technology, a tool, a means to an end. "Semantic Web" is our name for that end: a more semantic, ie. meaningful, Web. All RDF applications help, to some extent, in that direction, eg. since users of the technology (eg. by supplying feedback on specs, bug reports and encouragement to tool developers) help our collective efforts. If some RDF projects and applications are "more Semantic Webby" than others, I think the distinction is most usefully made in terms of thinking about contributions to the larger Web project, begun 15 years ago. The Semantic Web effort is explicitly part of this shared enterprise, and RDF projects which emphasise the Web (open, free exchange of data, collaboration, shared tools and interfaces, freedom from data lock-in, pluralistic technology that allows diverging views to share infrastructure, etc.) are particularly valuable contributions to the Semantic Web initiative. > My limited googling and research seems to indicate that the semweb > community itself is a bit fuzzy on the question too. True? I think there's a little truth in that. Many in the Semantic Web community at the moment are particularly excited by the possibilities raised by formal, machine-friendly representations of meaning. In particular, the sorts of simple rules that can be expressed in OWL ontologies and languages such as N3. There has in the last few years been a lot of attention given to the "Semantic" part of "Semantic Web", perhaps at the expense of the "Web" aspects. But it all balances out over time, and RDF data is usable as data regardless of whether it is consumed by a fancy, inference-capable KR system, or a simpler data-oriented triple store. So sometimes "Semantic Web" can get seem to just mean "that inference and logic and ontology" stuff, a characterisation which has led some cautious, skeptical or just data-centric folks to characterise their efforts as "RDF but not Semantic Web". FWIW, I concern the FOAF project (http://www.foaf-project.org/) to be a Semantic Web effort, a contribution to this larger project to improve the Web. It uses RDF, RDFS and OWL to help make "homepage-like" data more suited for machine processing, and in doing so helps people create RDF descriptions of both people and documents, amongst other things. In this sense, I think it would fall under your definition of non-semweb. But it really is intended as a practical contribution to the semantification of the Web... Not sure if this helped, but it's late so I'll stop scribbling and send. cheers, danbri
Received on Saturday, 18 December 2004 01:44:49 UTC