<http://schema.org/interactionType>
"http://schema.org/CommentAction"^^<http://www.w3.org/2001/XMLSchema#string>
<http://thenextweb.com/apps/2012/10/24/kindle-app-for-ios-gets-cool-x-ray-feature-but-just-for-textbooks-with-japanese-support-and-more/>