Metatag Commerce sandbox: https://drupal.org/sandbox/rvallejo/2102725
I've created a simple module to expand on the Metatag module to provide better support for commerce sites.
Currently the only thing DC-specific are some defaults I've set for some of the tags, but I'm also planning on adding a default Product Display configuration and would like to enable support for Product entities for the Metatag module. I welcome feedback and co-maintainers if anyone is interested.
I'm still in the process of developing it a little more. So far, tags included in the sandbox:
I also have the following tags in my working copy, which I'll commit later on today:
twitter:card "product", option added to available card types.
I expect some defaults will need tweaking to work with a more generic setup. I've been working on this to enable Pinterest rich pins, Twitter Cards, etc. for better integration with social networks.
I've also included a fix for og:image and twitter:image tags to split multiple images into multiple tags rather than a comma-delineated list (code originally written by fiftyz over at https://drupal.org/node/1305402#comment-6420040). I included the code as it's necessary to work with social networks, and because fiftyz's code only made the fix for open graph images -- eventually, the fix will probably be in the appropriate Metatag submodules.