This study notes the growing importance of online community as a means of building customer relationships. The author aims to identify how to communicate in an online community on preannounced new products, and test social influence that influence word-of-mouth of consumers, and confirm moderate effect of market maven between social influence and word-of-mouth activity in on-line community. The main findings are that social influence such as internalization and conformity positively influence word-of-mouth communication on online community. And moderate effect of market maven confirm between social influence(internalization and confirmity) and word-of-mouth activity.