An open protocol protocol is not valid XHTML 1.0 Strict?

Question

Protocol:

http://opengraphprotocol.org/

indicates the use of <meta> tags with the property attribute.

AFAIK, this is not a valid XHTML 1.0 Strict value. Is there a constructive solution as to why it doesn't use the name attribute instead? It seems trivial to me.

Answer 1

It uses RDFa for markup. There is an XHTML profile to resolve RDFa if you really want to check.