What We Know and Don't Know About Online Word-of-Mouth: A Review and Synthesis of the Literature

•Provide an extensive review of eWOM literature.•Provide the key characteristics of eWOM and their implications for research.•Provide insights into the antecedents and consequences of eWOM for both sender and receiver.•Identify key research questions for future research.

Electronic word-of mouth (eWOM) has attracted considerable interest from researchers in the past decade. Although the extant research has helped us to develop a good understanding of a number of the issues pertaining to eWOM, several research and managerial questions remain. Furthermore, no attempt has been made to consolidate and synthesize this stream of research. With consumers' increasing reliance on online retailing and information seeking, as well as the continued growth of social media, the importance of eWOM cannot be overstated. Based on a systematic review of 190 studies, we conduct a multi-dimensional analysis of eWOM communication. We present the key issues in current and emerging literature and propose important questions for future research.