This document discusses word of mouth marketing. It begins by defining word of mouth as interpersonal communication about brands, products, or services that can be positive or negative. It then explains the importance of positive word of mouth for businesses, such as free marketing and increased goodwill. However, negative word of mouth can damage a company's image and spread more quickly. The document also covers types of word of mouth marketing, determinants of word of mouth, and new trends like social media, blogging, and cause marketing. Real business examples of word of mouth's impact are provided.