Updated Oct 3 2008: link

The first thing I saw was, "To help in the search for Steve Fossett, please click here ... ". It is not a joke - it is serious.

The next thing was, "Complete simple tasks that people do better than computers. And, get paid for it. Learn more." Yes indeed.

From the site's answer to "What is Mechanical Turk":

From the site:

DBpedia is a community effort to extract structured information from Wikipedia and to make this information available on the Web. DBpedia allows you to ask sophisticated queries against Wikipedia and to link other datasets on the Web to Wikipedia data.

Their demo page for the subject Semantic Web, using DBpedia's Linked Data Interface format.

Freebase is a very powerful environment for data storage and classification. From their site:

Freebase is a uniquely structured database that you can easily search, add to and edit; you can also use the data in it to power your own projects. It’s a data commons in the way that a public square is a land commons—available to anyone to use.

Opera has several browser plugins and lively projects to build support for the Semantic Web.

One of most interesting plugins is the Tabulator RDF Browser Plugin. It's one of the few RDF tools that actually works.

The Tabulator Developers Notes ( and source code ) at MIT's DIG-CSAIL.

Not sure if WordNet qualifies as the "Semantic Web", but it's definitely semantic whatever the format may be. From the site ( paraprased )

WordNet® is a lexical database containing nouns, verbs, adjectives and adverbs. They aregrouped into "synsets" ( sets of cognitive synonyms ) each expressing a distinct concept. Conceptual-semantic and lexical relations build links between synsets. A browser navigates through the network of meaningfully related words and concepts.

From the site:

What is SchemaWeb?

SchemaWeb is a directory of RDF schemas expressed in the RDFS, OWL and DAML+OIL schema languages.

SchemaWeb is a place for developers and designers working with RDF. It provides a comprehensive directory of RDF schemas to be browsed and searched by human agents and also an extensive set of web services to be used by software agents that wish to obtain real-time schema information whilst processing RDF data.

Updated: Oct 4 2007

The most complete and developed example of the Semantic Web to date is probably Semantic MediaWiki at ontoworld.org. Note that its vision is in the Wiki on Steriods school of thought, which is one of several overlapping but distinct visions. From the site: