Social media is a great way to get the attention of a business. When I get great reviews for my yoga studio on Google or Yelp, I am always grateful for the feedback. I have not received any negative comments but I know if that ever happens, it is still useful information that can help me improve my business. I would respond to a negative comment because I care about the experience of everyone that visits the studio and I would try to find a way to address whatever happened to create that negative perception.
In fairness to any business, I would give them a chance to address any issue before I posted a negative comment. I am currently having an issue communicating with a business so I will try to work it out with them but if that doesn't work, I will try posting on their social media and see if I get a better response. Social media is a great tool for allowing the consumer to be heard as well as helping a business grow. People will believe their friend's opinion of a business before they believe an advertisement so it really gives the consumer a great way to make themselves heard.