rel-license

rel="license"

Rel-License is a simple, open, format for indicating content licenses which is embedable in (X)HTML, Atom, RSS, and arbitrary XML. Rel-License is one of several microformat open standards.

Draft Specification 2005-02-06

Author

Tantek Çelik, Technorati, Inc. (formerly of Microsoft Corporation)

Copyright

This specification is (C) 2004-2024 by the authors. However, the authors intend to submit (or already have submitted, see details in the spec) this specification to a standards body with a liberal copyright/licensing policy such as the GMPG, IETF, and/or W3C. Anyone wishing to contribute should read their copyright principles, policies and licenses (e.g. the GMPG Principles) and agree to them, including licensing of all contributions under all required licenses (e.g. CC-by 1.0 and later), before contributing.

Patents

This specification is subject to a royalty free patent policy, e.g. per the W3C Patent Policy, and IETF RFC3667 & RFC3668.

Abstract

Rel-License is one of several MicroFormats. By adding rel="license" to a hyperlink, a page indicates that the destination of that hyperlink is license for the current page. E.g. with the following hyperlink:

<a href="http://creativecommons.org/licenses/by/2.0/" rel="license">cc by 2.0</a>

the author indicates that the page is licensed under a Creative Commons 2.0 Attribution Required license.

Multiple Licenses

Multiple such rel="license" hyperlinks indicate that the page is available under any of the referred licenses. E.g. the following hyperlinks could be used to declare that a page is available under either a Creative Commons 2.0 Attribution Required license or the Apache 2.0 license:

<a href="http://creativecommons.org/licenses/by/2.0/" rel="license">cc by 2.0</a>
<a href="http://www.apache.org/licenses/LICENSE-2.0" rel="license">Apache 2.0</a>

XMDP profile

<dl class="profile">
 <dt id="rel">rel</dt>
 <dd><p>
   <a rel="help" href="http://www.w3.org/TR/html401/struct/links.html#adef-rel">
     HTML4 definition of the 'rel' attribute.</a>  
   Here is an additional value.</p>
  <dl>
   <dt id="license">license</dt>
   <dd>Indicates that the referred resource is a license for the referring page.</dd>
  </dl>
 </dd>
</dl>

Implementations

• pnh_mf is a plugin for Textpattern that supports embedding rel license and other microformats in templates and blog posts. Written by Chris Casciano.
• Creative Commons (cc) license chooser
• Yahoo! (cc) search
• Google "Usage Rights" search

References

Normative References

• XMDP

Informative References

• 20040211 rel="license" first proposed in presentation real world semantics at 2004 O'Reilly Emerging Technologies Conference, San Diego, CA, USA.
• 20040225 Thorough discussion of rel="license" including advantages and presentation possibilities.
• Creative Commons 2.0 By (Attribution Required) license
• Apache 2.0 license
• Contributed from http://developers.technorati.com/wiki/RelLicense

see also

• See rellicense-issues for issues which have been raised with this microformat.