Although previous studies have concluded that social media really does a shoddy job at driving traffic to your websites, TastyPlacement conducted a short experiment to assess a similar concept. More specifically, the group investigated whether social media engagement can help boost a website's organic search engine ranking.
To see if you can really drive up an organic search engine ranking using some social media sites you may have heard of, TastyPlacement created about as controlled of an experiment as you could do within the vast petri dish that is the internet. As it turns out, collecting Google+ followers seems to be the best way to push a site's ranking up by as much as 14.63%. Facebook and Twitter showed signs of improving organic search results but not nearly to the degree of promoting via Google+ followers (canvasing for +1s on Google+ resulted in a slightly lesser push in search ranking, but still wasn't too bad). The only promotional strategy that didn't seem to improve a site's ranking was by recruiting Twitter followers.
Have a look at the full infographic detailing the experiment and its results done by TastyPlacement, and feel free to comment with any of your experience or thoughts below.