People share billions of pieces of content such as news, videos, and photos through social media every day. Marketers are interested in the extent to which such content propagates and, importantly, which factors make widespread propagation more likely. Extant research considers various factors,...

This thesis contains three separate essays that deal with word of mouth. In the first essay, "Promotional Chat on the Internet," we analyze the firms' incentives to anonymously supply positive reviews of products in chat rooms and other recommendation sites. This, in turn, lowers the credibility...