Electronic word-of-mouth communication has a powerful impact on service industries. This study specifically examines negative messages on Internet forums to determine the impact of service characteristics (high versus low perceived risk), message types (affective versus instrumental), and consumer reading motives (informational versus interpersonal) on opinion acceptance, boycott intentions, and transmission intentions. Consumers have higher boycott intentions toward high perceived risk services after they read negative messages. Moreover, instrumental messages are more influential than affective messages, and consumers driven by interpersonal motives are more likely to transmit messages than are those driven by informational motives. Finally, a significant interaction effect exists between message types and reading motives.