I'm not sure I agree with this study 100%, but it is interesting. The summary is that interactions on social media sites are hugely important in search rankings. Visit mediabistro's AllTwitter blog.
Search engine optimisation (SEO) is all about the quality of your backlinks, right?
Wrong. Not any more. At least, not wholly, as an updated study from those good people at Searchmetrics has revealed just how important social media signals are to a strong SEO ranking, with well-positioned URLs almost always having a high number of Likes, shares, tweets and +1s.
All those Facebook Likes, Shares and Comments, Twitter Tweets, Google +1 and Pinterest pins are up at the top of the list of important factors in SEO. In fact, the number and quality of your backlinks is no longer at the top of the list as has always been.
Where I am confused and not sure I agree is whether these factors are independently causing high SEO rankings or if a certain page or site is getting lots of social engagement because they are listed first in the results. For me, this is a causation vs. correlation thing.
Taking it a step further, I don't think it would be smart for search engines (like Google) to pay that much attention to social likes and shares and let it affect their results pages. After all, it is probably much easier to game the social media links. At least, it seems easier than building fake backlinks.
You be the judge.