I've implemented Open Graph tags and Twitter Card tags on my site. The only way for the Twitter Card tags to validate as HTML5 is by changing them from ...name="twitter:card"... to ...property="twitter:card"... However, this causes Facebook's Open Graph Debugger to:
Open Graph Warnings That Should Be Fixed Extraneous Property: Objects of this type do not allow properties named 'twitter:card'.
Are Open Graph tags, Twitter Card tags, and HTML5 incompatible?