Hope you don't mind if I ask you here, I can't find your email. I saw on your twitter feed you recommended two great non-obvious resources for SEO - In the Plex

Hope you don't mind if I ask you here, I can't find your email. I saw on your twitter feed you recommended two great non-obvious resources for SEO - In the Plex and schema.org. An other resources (sites/books/etc.) you can recommend?