This article from Quicksprout, is a point in case. I'm not picking on Neil here, it's just one of dozens of articles I've seen telling me the same thing.
Neil says, a Moz article was #400 and jumped to the first page on Google for the term “Beginner’s Guide” after Smashing Magazine tweeted out the guide.
How is this possible? Well according to Neil, "Because both Google and Bing use data from social sites in order to determine how high to rank your website."
This is a direct contradiction to what Matt Cutts says. According to him, "Facebook and Twitter pages are treated like any other pages in our web index so if something occurs on Twitter or occurs on Facebook and we're able to crawl it, then we can return that in our search results. But as far as doing special specific work to sort of say “you have this many followers on Twitter or this many likes on Facebook”, to the best of my knowledge we don't currently have any signals like that in our web search ranking algorithms."
It's generally recognised that there are hundreds of ranking factors. Does that mean that these factors go out the window and that 1 tweet can rank you on the 1st page of Google for the term "Beginners Guide"? Absolutely NO chance.
It's easy to manipulate Twitter and other social signals. Google never has and never will rely entirely of the data from third parties and this is exactly what Neil is saying they are doing. Google is ranking content purely on the data from social signals.
I think we are talking about correlation here. If you Tweet something and 50,000 people share it, it's bound to attract links and links are the backbone of Google's algorithm. It's the indexable links that rank content, not "social signals" in them selves.
To me it's no surprise that the results in Buzzmo bear no relation to the results in Google's serps in most cases.
Is it any wonder that the people who publish these "studies" are actually in the business of social media marketing?
Have you seen an example of competitive content ranking without any links and purely on social signals? If you have, I'd be interested in seeing it.