Like the World Wide Web, the Semantic Web is decentralized -- no one organization or agency has control over all of its rules and content. However, some people and organizations have taken leadership roles in the development of Semantic Web guidelines and protocols. These include the World Wide Web Consortium (W3C), its director Tim Berners-Lee and its member organizations. The W3C is not a research organization, so universities, other organizations and the public also play an active role in Semantic Web development.
Some areas of the World Wide Web have already incorporated Semantic Web components. These include RSS feeds, which use RDF, and the Friend-of-a-Friend (FOAF) project, which proposes to create machine-readable personal web pages.
But much of the Semantic Web's function and practicality are still in development, and there are some pretty big obstacles to overcome. Decentralization gives developers the freedom to create precisely the tags and ontologies that they need. But, it also means that different developers might use different tags to describe the same thing, which could make machine comparisons difficult. Critics also question the "identity problem" -- does a URI represent a Web page, or does it represent the concept or object the page describes. For example, is "http://www.starwars.com" meant to represent the "Star Wars" films, or just the Web page?
Some developers disagree on whether the Semantic Web should rely more heavily on rules or on ontologies. Critics also say that the project is enormously impractical. First, people don't actually think in terms of the graphs that RDF uses. Second, it seems unlikely that businesses and existing sites will actually devote the time and resources it would take to add all the necessary metadata. In the future, off-the-shelf software might include options for adding metadata when creating new documents, but that tool still might not make the project feasible on a larger scale.
For lots more information on the World Wide Web and the Semantic Web, check out the links below.
More Great Links
- Adams, Katherine. "The semantic Web: Differentiating between taxonomies and ontologies" Online; Jul/Aug 2002;
- Beckett, Dave. "Dave Beckett's Resource Description Framework (RDF) Resource Guide." http://planetrdf.com/guide/
- Clark, Kendall. "SPARQL: Web 2.0 Meets the Semantic Web" O'Reilly. http://www.oreillynet.com/pub/wlg/7823
- Greenberg, Jane et al. "Metadata: A Fundamental Component of the Semantic Web." Bulletin of the American Society for Information Science and Technology, Apr/May 2003.
- Greenberg, Jane. "Metadata Generation: Processes, People and Tools." Bulletin of the American Society for Information Science and Technology, Dec 2002/Jan 2003.
- Greenberg, Jane. "The Semantic Web: More than a Vision." Bulletin of the American Society for Information Science and Technology, Apr/May 2003.
- Gruber, Tom. "What Is an Ontology?" http://www-ksl.stanford.edu/kst/what-is-an-ontology.html
- Hardin, Steve. "Tim Berners-Lee: The Semantic Web - Web of Machine-Processable Data." Bulletin of the American Society for Information Science and Technology, Feb/Mar 2005
- Hawke, Sandro. "How the Semantic Web Works." http://www.w3.org/2002/03/semweb/
- Hendler, James. "Science and the Semantic Web.' Science. Jan. 24, 2003.
- Horrocks, Ian et. Al. " Semantic Web Architecture: Stack or Two Towers?" http://www.cs.man.ac.uk/~horrocks/Publications/download/2005/HPPH05.pdf
- Jacob, Elin K. "Ontologies and the Semantic Web." Bulletin of the American Society for Information Science and Technology; Apr/May 2003.
- Miller, Eric and Ralph Swick. An overview of W3C Semantic Web activity." Bulletin of the American Society for Information Science and Technology, Apr/May 2003.
- Parsia, Bijan. "Semantic Web Services." Bulletin of the American Society for Information Science and Technology, Apr/May 2003.
- Shirky, Clay. "The Semantic Web, Syllogism and Worldview." http://www.shirky.com/writings/semantic_syllogism.html
- Swartz, Aaron. "The Semantic Web in Breadth." http://logicerror.com/semanticWeb-long
- Van Eman, Jay. "OWL Exports from a Full Thesaurus." Bulletin of the American Society for Information Science and Technology, Oct/Nov 2005.
- W3C: How We Identify Things on the Semantic Web. http://www.w3.org/2001/03/identification-problem/
- W3C: OWL Web Ontology Language Guide http://www.w3.org/TR/owl-guide/
- W3C: RDF Primer http://www.w3.org/TR/rdf-primer/
- W3C: Semantic Web Activity Statement. http://www.w3.org/2001/sw/Activity
- W3C: SKOS Core Guide http://www.w3.org/TR/swbp-skos-core-guide/
- W3C: Tutorial on Semantic Web Technologies http://www.w3.org/Consortium/Offices/Presentations/RDFTutorial/