Back in Scientific American featured an article by Tim Berners-Lee and others on the possibilities offered by the semantic web. Last month's issue (Dec 07) featured an article by Lee Feigenbaum and others which gives a good overview of progress towards that early vision. The article is online but for a fee: http://www.sciam.com/article.cfm?id=the-semantic-web-in-action.
The article talks about how the development of standards (RDF and OWL) has spurred developments in the commercial sector. A number of large organisations are now using ontologies to manage information and deliver content. It also talks about how the semantic web can build on the popularity of tagging on social sites such as Facebook and Flickr as RDF and ontologies are maturing.
The article features two interesting case studies in drug discovery; and health care. A common theme across both case studies is the volume of data/information. It'd be interesting to learn more about the contribution text mining can make to the Semantic Web vision - the BOOTStrep project at NaCTeM is exploring the role of text mining in ontology development, for example.
Other interesting applications mentioned include: Science Commons (semantic web tools for attaching copyright and licensing info to data) and DBpedia (linking information within Wikipedia).
Their conclusion? "Grand visions rarely progress exactly as planned, but the Semantic Web is indeed emerging and is making online information more useful than ever".