But it would probably be better to point to this 2011 post (also from SEOMoz/Moz) from two years ago in which a similar claim was made about Facebook shares: http://moz.com/blog/does-google-use-facebook-shares-to-influ... . From that blog post from two years ago: "One of the most interesting findings from our 2011 Ranking Factors analysis was the high correlation between Facebook shares and Google US search position."
This all came to a head at the SMX Advanced search conference in 2011 where Rand Fishkin presented his claims. I did a polite debunk of the idea that Google used Facebook shares in our web ranking at the conference, leading to this section in the 2011 blog post: "Rand pointed out that Google does have some access to Facebook data overall and set up a small-scale test to determine if Google would index content that was solely shared on Facebook. To date, that page has not been indexed, despite having quite a few shares (64 according to the OpenGraph)."
If you make compelling content, people will link to it, like it, share it on Facebook, +1 it, etc. But that doesn't mean that Google is using those signals in our ranking.
Rather than chasing +1s of content, your time is much better spent making great content.