It has been many years since the original idea was proposed (back in 2004) but RDFa is now a full fledged citizen of the W3C. It reached Recommendation status on 14th of Oct. The W3C uses the word recommendation, but essentially it means standard to the rest of us :)
There is a lot of work yet to be done in the educational materials on RDFa. The concentration has for so long been in getting the spec in order that the examples and howtos have suffered.
I think this situation will change rapidly as there will be a lot more interest and with that comes increased traffic and hopefully more tutorials. Dries Buytaert (of Drupal fame) has just posted a wonderful road map for the Semantic Web in Drupal 7. It talks about the future of search and how quickly and painlessly any Drupal site will automatically participate.
Here is a list of some examples that should help you out:
- An example of marking up audio, music and albums
- The all important FOAF howto. Turn your home page into your Semantic Web identity quick like!
- Calendar events
- Creative Commons (CC) licensing
SearchMonkey recommends the use of these RDF vocabularies:
- dc – Dublin Core
- foaf – Friend of a Friend
- vcal – Calendar events
- sioc – Semantically Interlinked Online Communities
- gr – GoodRelations: Product price specification, delivery and payment etc.
- dbpedia – Semantic Web version of wikipedia
- fb – freebase – structured wiki with an amazing interface