author vs. creator

Can anyone tell me what the difference is between "creator" and "author" in schema.org microdata, and under what circumstance I would ever use "creator" rather than "author"?

I've scoured all the schema.org page pages and there's not a single code example that uses "creator" in the code.

Here are the (infuriatingly vague, IMHO) descriptions of the two properties listed under CreativeWork:

author
The author of this content. Please note that author is special in that HTML 5 provides a special mechanism for indicating authorship via the rel tag. That is equivalent to this and may be used interchangabely [sic].

creator
The creator/author of this CreativeWork or UserComments. This is the same as the Author property for CreativeWork.

And a related CreativeWork property:

sourceOrganization
The Organization on whose behalf the creator was working.

No further clarity is to be gained from Google's Recipe example that actually mentions "creator", though not as a property [1].

Under properties recognized:

Property - author
Description - Creator of the recipe. Can include nested Person information.

data-vocabulary.org markup example:
By <span itemprop="author">Carol Smith</span>

So - again - under what circumstances would one use "creator" instead of "author"?  And if the answer is "they're fully interchangeable" why is "creator" part of the schema?

By the way, I'm aware of the DublinCore dc:author element, and it's relationship to the RSS "author" element [2] (the former being less restrictive than the latter), but I can't see why the existence of dc:creator would cause the property "creator" to surface in the schema.


[1] http://support.google.com/webmasters/bin/answer.py?hl=en&answer=173379

[2] http://www.rssboard.org/rss-profile#namespace-elements-dublin-creator

Thanks!
Aaron Bradley

Received on Monday, 30 April 2012 19:54:31 UTC