Changes in the SEO land: Quoting Google webmaster's guidelines: Used to be: “In general, webmasters can improve the rank of their sites by increasing the number of high-quality sites that link to their pages.” Now: “In general, webmasters can improve the rank of their sites by creating high-quality sites that users will want to use and share.” http://moz.com/rand/googles-updated-seo-advice-is-almost-correct/ Awesome stuff.
The biggest clue to help clarify further the way it has always been being > users will want to use and share.
That's nothing new really...they just reworded it, but sharing a site because it's useful will automatically get you backlinks...lol Holla!
The thing is it pretty much reduces your advertising pool. Obviously, the only good places users can share your site will be: FB, G+, twitter, reddit, SU and maybe a couple more. So, if nobody shares you there, you're pretty much out of luck. No?
Basically one could infer that they're about to change the algorithm to favour social backlinks (links and popularity on social media) vs. links from websites.