My current research efforts involve the semantic Web and ontologies. By the semantic Web I include that topic, plus the related technologies and standards of metadata, ontologies, taxonomies, thesauri, controlled vocabularies, XML, RDF and OWL.
A good starting point on tools is from Michael Denny, which is an update of his 2002 ontology editor survey. Other tools surveys include a 2003 HP review from the SIMILE research program on metadata and thesaurus tools; the Semantic Web has a listing of about 245 tools on its beta Web site; and the W3C, as might be expected with its role in RDF and related standards, has an excellent starting point for developer resources, including entries for related standards and technologies.
The ONTOLOG community also lists some tools resources, but more importantly has a very excellent recommended reading compendium. These links are essential starting points for anyone beginning their investigations into the semantic Web.
Finally, Kendall Clark, editor of XML.com, just posted a fascinating piece on SPARQL 2.0, a possible query language to the semantic Web and a longer article on the possible convergence of Web 2.0 and the semantic Web. As he puts it, I’m starting to catch the scent of one of those big convergence things just possibly starting to happen. It smells like money!