Social media signals from Facebook, Twitter and Google+ correlate very strongly with Google search rankings, higher than keyword rich header tags, backlinks with keywords, on-site images and page descriptions, a recent study has found.
Looking at 10,000 selected keywords, 300,000 websites and millions of links, tweets and shares, Searchmetrics found Facebook shares, likes and comments to be among the highest of social signals to correlate with high search engine rankings. Tweets were found to be the sixth most correlated factor in the study.
Interestingly, Google+ social signals were shown to have the highest correlation with high search rankings, however given the small active user base and relative newness of the network, Google+ was left out of the results.
Whilst correlation of course does not guarantee causation of the high search rankings, the study does highlight a strong relationship between the SERPs and social media signals. With Google's Matt Cutts repeatedly stating that social media signals are taken into account in both organic and news rankings, the relationship between SEO and Social Media will continue to grow.
(Image from Searchmetrics.com)