I'm aware that Google have addressed this before and specifically said that social signals are not a ranking factor: http://searchenginewatch.com/sew/news/2325343/matt-cutts-facebook-twitter-social-signals-not-part-of-google-search-ranking-algorithms
However I came across this (admittedly great) infographic from Neil Patel, an SEO I have a lot of respect for: http://www.quicksprout.com/2014/01/31/how-social-signals-impact-search-engine-rankings/
In the post he specifically states that "both Google and Bing use data from social sites in order to determine how high to rank your website."
I have always understood that social signals help drive links by spreading your content to a bigger audience, thereby getting your content in front of people who are likely to link. I also appreciate that content that is shareable is also likely to be linkworthy.
However. Neil doesn't talk about correlation here, he talks about social signals as a ranking factor. Is he being misleading, or has the game changed since Matt Cutts said they don't use social signals?