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