To what extent does activity on Social Media platforms impact SEO?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Yasser Mohamed: Could just be a co incidence but since joining Google + a couple of weeks ago we have managed to hit page 1 for a highly competitive keyword. ; This didn't happen with Facebook, Twitter or LinkedIn - which we have been using much longer than Google +. ; I have also noticed my search results now say how many circles I am in and who has +1'd me.
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  Tim Capper: I personally dont think that LKD, Twit, FB have anything to do with Ranking.
  
  In theory G+ Business page should not have any influence either, but on implementing rel=publisher, all sites I manage have bumped up 2 positions on avareage 30 days after implementing.
  
  I do know that rel=authorship (authorship) has increased my CTR and time on site.
  
  Google+ in some instances provide follow links back to site also.
  
  I would recommend integrating and using G+ strongly to any business - the others are up to them and each have their own set of users that might benefit the business.