This document summarizes a study on word-of-mouth (WOM) and social influence on Facebook. The study examined WOM at both the individual and network levels. At the individual level, it looked at identifying influential users and their characteristics. It found that an observation method of influence was more valid than self-designation. At the network level, it developed a structural social influence model of Facebook WOM incorporating direct contact, interpersonal contagion, and network embeddedness. The model was tested on a network of nearly 4,000 users to understand how social network factors influence WOM.