Social media has emerged as one of the biggest phenomenon in the world of communication and marketing. Billions of people are using different social media websites on a daily basis. Consumers also refer to reviews of products and services on social media before making purchase decisions. This book investigates how consumers get influenced by the reviews that they read on social media. Based on extant literature a conceptual model of social media WOM is presented and then the research hypotheses are empirically validated using experiments. Role of source credibility, social media website, product knowledge and involvement level are also explored in this context.