Although the online commenting system is generally regarded as a place for discussion, there should be empirical evidence that its components, such as comments, responses, and replies, are not unrelated fragments of the system but interrelated elements of the discussion. Using Habermas' public sphere theory and data from Korean news portal sites, we demonstrate that comments, responses, and replies all contribute to an online discussion by being in the discussion stages. Overall, the analysis of their relationship illustrates that comments that are likely to receive responses are more likely to receive replies. Furthermore, more responses and replies are followed when people disagree with the comments. Therefore, our findings show that comments, responses, and replies build the online discussion and that people discuss more when they disagree, suggesting that the commenting system becomes the place for online discussion.