No I don't mean discoverability (although, that too) and no I don't think search engines are involved at all. They link to the content, they don't host it. Fac

No I don't mean discoverability (although, that too) and no I don't think search engines are involved at all. They link to the content, they don't host it. Facebook hosts the content and makes it available to the public. That is why they are special. None of the other steps do both