Syndication

License statements may be included in various synication formats, generally at the feed and item level, where the latter overrides the former.

RSS 1.0

http://web.resource.org/rss/1.0/modules/cc/

RSS 2.0

http://backend.userland.com/creativeCommonsRssModule

Atom 1.0

http://ietfreport.isoc.org/idref/draft-snell-atompub-feed-license/

Licensed Content Discovery

Not all feeds include license metadata. Heuristics for discovering licensed content. Perhaps useful in particular for aggregators:

• IF feed item contains license reference or feed contains top level license reference

 * THEN content in feed (including images and enclosures) probably licensed

• Crawl feed item URLs.

 * IF license found for feed item URL (e.g., rel="license")
   * THEN content at feed item URL probably licensed
 * IF license metadata found specifically for media (e.g., about an image or video URL)
   * THEN that media is probably licensed

• Download content referred to (e.g., in enclosure)

 * IF content contains reference to metadata on the web that says content is licensed, content is probably licensed (see Embedded Metadata

This is obviously just a sketch. Aggregators may wish to use different heuristics for different feeds. See Content Curators for some sites with feeds of CC licensed content.