RDFa

RDFa (Resource Description Framework in Attributes) is an extension to HTML 5 to allow inclusion of metadata in the form of linked data. Unlike RDF, which is generally found as separate XML-based files, RDFa is a manner of formatting of data found within an HTML document.

A limited subset of RDFa, designed to be simpler for beginners, is RDFa Lite.

Links

 * RDFa 1.1 primer (W3C)
 * RDFa Lite 1.1 (W3C)
 * rdfa.info
 * Linked data (Wikipedia)
 * Copy RDFa Metadata (Firefox add-on)
 * Commons Machinery (initiative to tag image metadata in standardized way using RDFa)
 * elog.io: API to find missing attributions