RDFa

RDFa allows building metadata into XHTML and other XML documents with attributes. See also RelLicense.

References

• http://www.w3.org/2006/07/SWD/RDFa/primer/
• http://www.w3.org/TR/rdfa-syntax/
• RDFa.info
• Wikipedia article
• RDFa @ the W3 Wiki

Presentations

• http://ben.adida.net/presentations/w3c-2006-04-06/html/w3c
• http://ben.adida.net/presentations/semantic-2006-03-08.pdf
• http://skimstone.x-port.net/introduction-to-rdfa

Content discovery

A key use case for RDFa is the annotation of resources included or embedded in web pages. Existing annotations apply to the current document. For example, http://example.com/foo contains

<a rel="license" href="http://creativecommons.org/licenses/by/3.0/">cc</a>

This says that http://example.com/foo is licensed under CC BY 3.0. What about http://example.com/bar.jpg which is displayed in http://example.com/foo via a <img src="/bar.jpg"> element?

To specify that bar.jpg is licensed, even under a different license, we can qualify the link with an about attribute:

<a about="/bar.jpg" rel="license" href="http://creativecommons.org/licenses/by-nc/3.0/">cc</a>

Found in http://example.com/foo this says http://example.com/bar.jpg is licensed under CC BY-NC 3.0.

See Qualifying Other Documents and Document Chunks in the RDFa primer for more examples.

The RDFa highlighter bookmarklet provides visual cues for statements about included resources.

CC Tools

RDFa is used or supported in the following CC tools:

• MozCC (see What's New in MozCC 2)
• RdfaDict is a Python RDFa parser