Consumer opinions, experiences, and product recommendations posted on online WOM sites have become a major information source in consumer purchase decisions. However, prior research has largely focused on the influence of a single source of WOM – particularly retailer-hosted WOM. This study investigates the relative impact of multiple WOM information on retail sales. We collected a panel of sales data of 148 camera products from Amazon and WOM data from both Amazon and well-known third-party websites for four months. Our analysis reveals that thirdparty hosted WOM has a significant impact on retail sales while retailer-hosted WOM has much less influence on its own sales. Our finding suggests that third-party hosted WOM is an important source of information for online retail customers. We raise questions about the value and influence of retailer-hosted WOM in the presence of reputable third-party hosted WOM sources.