This study investigates how the politeness strategies of readers who comment on online news articles influence the participation and politeness behaviors of subsequent readers. We analyzed comments and replies collected from a South Korean news aggregator using a computer-mediated discourse analysis approach [15]; the gender of commenters was considered as a potential moderating factor. Results show that the politeness of comments did not affect the frequency of replies, and violations of politeness were prevalent in replies to all types of comments and addressees, especially in threads with mostly male participants. However, significant differences were found in responses to polite comments in maledominant versus female-dominant discussions. Polite comments served as a catalyst for active participation by repliers, but only when men dominated the discussions, and these comments elicited harsh replies. Conversely, only when women participated more did any replies tend to use polite language, and that was only when addressing the original commenter.