RDFa (or Resource Description Framework – in – attributes) is a W3C Recommendation that adds a set of attribute level extensions to XHTML for embedding rich metadata within Web documents. The RDF data model mapping enables its use for embedding RDF triples within XHTML documents, it also enables the extraction of RDF model triples by compliant user agents.—– Wikipedia
RDFa Primer (中文), About RDFa – Google, SearchMonkey support RDFa Enabled