Recently the Wall Street Journal wrote about social media and a related Gallup Poll. http://online.wsj.com/public/resources/documents/sac_report_11_socialmedia_061114.pdf
Basically is the survey shows that the majority of respondents claim to not be influenced by social media postings by brands. This is even true of millenials. It appears that brands are using traditional methods in a new media space. They broadcast en mass hoping for a few listeners.
Simply put social media is not an easy path to instant new customers. It can have great potential but only if it is aligned with other channels of communication and reality. To make social media work for the company, brands should use it to enable their loyal customers to avocade on their behalf. No form of communication replaces relevant services excellently executed.