As Google and other search engines keep trying to get more and more 'human' in terms of understanding what's good and what's spam, is it known if they take into account the size of a heading ie. an thats font size is 40px is going to speak a lot more to the user than a thats font size is 14px?
Similarly, does placement of text factor? E.g. a 300-word article at the bottom of a landing page (not in the footer but below the useful content) would be there just for seo purposes?
I know they look at things like text-indent:-9999px; and white text on a white background, but what about these more border-line practices that both have legitimate uses, but also the possibility to be spammy?