Ora Lassila and James Hendler, who co-authored along with Tim Berners-Lee, on the article which predicted what the semantic web would look like in 2001, argues in their most recent article, Embracing "Web 3.0" that the technologies that make it possible for the semantic web is slowly but surely maturing. In particular,
As RDF acceptance has grown, the need has become clear for a standard query language to be for RDF what SQL is for relational data. The SPARQL Protocol and RDF Query Language (SPARQL), now under standardization at the W3C, is designed to be that language.
But that doesn't mean that Web 2.0 technologies are obsolete. Rather, they are only a terminal stage of the evolution to Web 3.0. In particular, it is interesting that the authors note
(1) Folksonomies - tagging provides and organic, community-driven means of creating structure and classification vocabularies.
(2) Microformats - the use of HTML markup to decode structured data are a step toward "semantic data." Of course, although not in Semantic Web formats, microformatted data is easy to transform into something like RDF or OWL.
As you can see, we're moving along. Take a look at this: on the surface, Yahoo Food looks just like any Web service; underneath, it is made from SPARQL which really does "sparkle."