This is probably just an iteration on earlier methods of prioritizing a page's content. Previously, Google would place a higher priority on content that came t

This is probably just an iteration on earlier methods of prioritizing a page's content. Previously, Google would place a higher priority on content that came towards the beginning of a page. As users became aware of this, they then began organizing their code so that the most SEOable content was at the beginning of the HTML file, but used CSS to make sure that the what users saw as the beginning of the page was still optimized for people. Presumably, now Google is checking to see which parts are actually styled to appear at the beginning, regardless of order in the source files.