RDFa annotates pages not elements

[michael-n-cooper]

I recently submitted a pull request #50 to describe how to use the personalization semantics vocabulary in HTML Microdata and RDFa. I have since been told by a RDFa expert that RDFa does not add semantics to the element it is used on; instead, it describes how to use content from that element to add semantics to the page as a whole. This would mean that RDFa would not be a useful metadata language for most of the use cases we have for personalization semantics. I still need to learn more about this but wanted to log an issue.

If RDFa only annotates the page as a whole, then we should explore if there are features of personalization semantics for which that is useful. My guess would be that personalization at a page level would be a different kind of module from the others, and we might say RDFa could be used only for that module. This is likely to benefit use cases that impact search engines (e.g., pointers to alternate versions of content and the nature of the alternative) rather than direct user experience in user agents.