Social media is changing the game.  For the last decade, search engines, in general, and Google specifically have been driving most of the traffic to content producing sites likeYahoo and MSN.   But, that has changed with more than 400 million people on Facebook, and people sharing news and stories through that platform.  Users are relying more heavily on the recommendations of friends than their own Internet browsing.  This is a trend that should be noticed as SEO and a company's social media presence are both critical to a successful marketing campaign.