When I run a page for which I've set up Open Graph meta tags through https://developers.facebook.com/tools/debug I get:
Errors That Must Be Fixed
Meta Tags In Body: Your page has meta tags in the body instead of the head. This may be because your HTML was malformed and they fell lower in the parse tree. Please fix this in order for the tags to be usable.
It seems to work Ok though. Is this a theming issue (using Fusion/Acquia Marina)?