"If your content is fresh and linked to from reputable sites, we'll promote you in the search results... for free."
Facebook is purely pay-for-play. Paying for boosted posts is the only way to cut through the noise (unless your content goes organically viral, which only has a 24 hr shelf life).
Some evolution images and stories: http://searchengineland.com/evolution-google-serps-three-key...
It is still "free" but takes a lot of work to get there, and it is worth less than it used to be. Lots of SEO's have gone the way of paid.