Notes for a History of RDFa

Steven Pemberton, 7 June 2012

The HTML WG was chartered to solve metadata in HTML problem; large community request for standard way to include RDF in HTML (some used comments, etc.)

Often referred to "metadata story": finding a consistent representation for metadata in HTML.


RDF Spec

"The recommended technique for embedding RDF expressions in an HTML document is simply to insert the RDF in-line. This will make the resulting document non-conformant to HTML specifications up to and including HTML 4.0 but the RDF Working Group hopes that the HTML specification will evolve to support this. "

RDF Requirements for RDF in HTML

"The discussion around the RDF requirements showed that possible solutions for RDF included putting all the information into attributes; putting it in an external file; and putting it at the end of the document. in general the participants thought that putting information into attributes was safer than putting it in an external file because of worries about security and forcing tools to be able to cope with multiple files. Since many tools already have to cope with multiple files, other participants thought this was not a drawback where security was not an issue. Some participants thought that putting the information in an external file would sometimes be a necessity, so tools would have to learn to cope."


At least Feb 2002 earliest version. Micah Dubinko Metadata for Grandma : Has @about, nested <meta>s, qnames in @name, uses element content in meta. WG agrees to add @about, make <meta> contentful.

June 2002, Sean Palmer summarises current thinking on embedding RDF in HTML

20 Nov, Steven Pemberton email:

Thanks for your comments. In fact RDF in XHTML is a current subject of discussion. Our current thinking is to use the <meta> element, but <link> may also be involved.


13 Feb, Steven Pemberton proposes nested meta approach to rdfcore group.

<meta rdf:about="">
    <meta name="dc:title">RDF/XML Syntax Specification (Revised)</meta>
    <meta name="ex:editor">
        <meta name="ex:fullName">Dave Beckett</meta>
        <meta name="ex:homePage"></meta>

7 March, HTML WG and SW group meet at TP : Agenda

Steven Pemberton: Goal is to represent all of RDF (with meta approach)

Steven: I think you'll get far greater use of RDF if it's exposed to the public in HTML.

Masayasu Ishikawa experiment with embedding RDF in XHTML

RDF in HTML Requirements from TF (lots of references here)

public-rdf-in-xhtml-tf taskforce email list created

9 July HTML WG call with Joseph Reagle present

Steven: RDF isn't actually a single syntax, there's at least three different syntaxes for triples. To what extent is RDF group moving to an abstract concept?

Mark Birbeck 24 Oct 2003 XHTML and Metadata

<span type="date" value="1940-06-04">Yesterday</span> in Parliament the <span value="">Prime Minister</span> said that we will fight on the beaches ...

Nov 2003

Steven: why don't we just use rdf:type and rdf:value?

"RESOLUTION: import all RDF properties as attributes."

ACTION: Mark work on his document to incorporate our discussions and agreements.


14 Feb 2004, Mark Birbeck HTML and RDF

Meet with SWIG at TP Steven's Diary: "We were worried that we would get hounded out, but it turns out they are very enthusiastic!"

March 2004, Mark and Steven present RDF/XHTML at XML Tech 2004, Amsterdam

July XHTML2 Metadata module Has rel, property, resource, about

11 Oct 2004, Mark Birbeck and Steven Pemberton publish (renamed) RDF/A Syntax


May: Mark and Steven present XHTML2 at XML Tech, including section on RDF/A


Apr: Rename to RDFa to make it Google friendly, talk on creating


October: FPWD of RDFa proper, produced jointly by the Semantic Web Deployment Working Group and the XHTML 2 Working Group.

Joost uses

Operator on FF supports


Feb - last call

Yahoo labs

Another FF extension

March: ODF, topbraid composer, Yahoo

March: public-rdfa mailing list created.

Apr: Digg, Fuzzbot

May UK Gov (London Gazette)

June: Open Archives, UK National Archive

Sep: Drupal announcement

Oct: Recommendation


Jan - Whitehouse

Mar - Dreamweaver, Slideshare, Myspace

May Ian Hickson suddenly, out-of-the blue, and without consultation produces incompatible microdata, using RDFa attributes.

May Google

Oct Public Library of Science

Dec Best buy; O'reilly Catalogue


Jan Tesco

Apr Facebook



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