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HTML Data Task Force

The HTML Data Task Force ran from October to December 2011. Two Notes were published as a result of this work:

This wiki is retained for capturing further developments. In particular, any errata on these documents can be recorded on the HTML Data Errata page and will be incorporated into those documents when they are revised, which will probably be after RDFa and Microdata reach Recommendation.


This HTML Data Task Force considers RDFa 1.1 and microdata as separate syntaxes, and conducts a technical analysis on the relationship between the two formats. The analysis discusses specific use cases and provide guidance on what format is best suited for what use cases. It further addresses the question how different formats can be used within the same document when required and how data expressed in the different formats can be combined by consumers.

The task force MAY propose modifications in the form of bug reports and change proposals on the microdata and/or RDFa specifications, to help users to easily transition between the two syntaxes or use them together. As with all such comments, the ultimate decisions on implementing these will rest with the respective Working Groups.

Further, the Task Force should also produce a draft specifications of mapping algorithms from an HTML+microdata content to RDF, as well as a mapping of RDFa to microdata's JSON format. These MAY serve as input documents to possible future recommendation track works. These mappings should be, if possible, generic, i.e., they should not be dependent on any particular vocabulary. A goal for these mappings should be to facilitate the use of both formats with the same vocabularies without creating incompatibilities.

The Task Force will also consider design patterns for vocabularies, and provide guidance on how vocabularies should be shaped to be usable with both microdata and RDFa and potentially with microformats. These patterns MAY lead to change proposals of existing (RDF) vocabularies, and MAY result in general guidelines for the design of vocabularies for structured data on the web, building on existing community work in this area.

The Task Force liaises with the SWIG Web Schemas Task Force to ensure that lessons from real-world experience are incorporated into the Task Force recommendations and that any best practices described by the Task Force are synchronised with real-world practice.

The Task Force conducts its work through the mailing list (use this link to subscribe or look at the public archives), as well as on the #html-data-tf channel of the (public) W3C IRC server. The Task Force maintains a list of issues and actions in the W3C tracker.

The Task Force is chaired by Jeni Tennison.