Draft POWDER Metadata Profile Reference

POWDER is a PrOtocol for Web Description Resources. It allows people or organizations to make semantic assertions about web resources, describing them in a file distinct from the resources themselves. For full details, see the POWDER home page.

This document, http://www.w3.org/2007/11/powder-profile, is a metadata profile in the sense of the HTML specification, in section 7.4.4.3 Meta data profiles.

Through usage of head profile="http://www.w3.org/2007/11/powder-profile" you indicate that your HTML document is described by a POWDER Descriptive Resource (DR). Use the HTML link/@rel tag with a value of 'powder' to declare the source of this DR, and, optionally, meta tags to state the DR's creator and any validity period. By inspecting this meta data, a machine process may determine whether to subsequently retrieve the full DR: for example, if the issuedby is a trusted source of descriptions and if the DR is still valid.

Example HTML usage:

<html>
 <!-- the head/@profile attribute declares that this document is described in a POWDER DR-->
  <head profile="http://www.w3.org/2007/11/powder-profile">
    <title>My Document</title>
    <!-- the meta tags declare metadata about the DR itself, *not* about this document. As such they are all bound to the POWDER namespace and use a 'wdr.' prefix-->
    <meta name="wdr.issuedby" content="http://example.org/trustedOrganisation" />
    <meta name="wdr.validFrom" content="2007-10-31T00:00:00" />
    <meta name="wdr.validUntil" content="2008-10-30T23:59:59" />            
    <!--... and finally the link to the POWDER document itself, which can then be retrieved to acquire the full set of descriptions about this document-->
    <link rel="powder" href="http://www.example.com/myDescriptions.xml" />
  <head>
  …
</html>

Acknowledgements

This document used the GRDDL profile, authored by Dan Connolly, as a template.