Category: semanticweb

Creative Commons Metadata

This site is licensed under a Creative Commons Attribution License, and I wanted to mark each page to somehow indicate that fact. recommends that we mark our pages using RDF data embedded in our HTML (commented out). However, embedding the RDF in each page has a few downsides:
  1. It increases the size of each page by a several hundred bytes.
  2. In xhtml pages, it potentially hides the copyright information from xml parsers.
As an alternative (which I didn't invent, I'm just describing), I link to the copyright information with metadata attributes to indicate its role. The pages on this site use 2 methods of specifying the copyright. In the <head> section, I included a <link> to the copyright URL with a rel="copyright" attribute. The copyright link type is defined in HTML4. For example:

<link rel="copyright" href="" />

The second method can be used within the body of the document. My footer section includes a link to the CC license. I added a rel="license" attribute to that link. The license relation is a common microformat.

To guarantee that search engines understand the licensing of my site, I ran a few of my URLs through Creative Commons License Validator tool. Everything checks out!

Finally, I also wanted my RSS feed to be covered by the CC license. There is a Creative Commons RSS Module defined for this purpose: you insert a


line into the <channel> section of your feed. I use XML::RSS to generate my feeds (this is a mod_perl/HTML::Mason site) to generate my feed, so I added code like this (new code is bolded):

my $rss = new XML::RSS (version => '1.0'); 

# add the creative commons namespace
$rss->add_module(prefix=>'cc', uri=>'');

       title        => "littleredbat/mk: blog",
       link         => "",
       description  => "Matt Keller's Blog",
       dc           => { language => 'en-us', },
       cc           => { license => '', },

There you have it - my site has been CreativeCommonsIfied.

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