Thanks for your response. Also that's cool you're probably right about meta tags open graph is broadly used but not uniform in their content. As for additional sites Stackoverflow and quora would be great additions.
I don't usually use Arxiv. Do you have some example queries where you would like to see a Arxiv column?
Also same with HN? That is a bit of a harder one. I guess I could trigger a HN column if there are tech news type results returned from Google.