This research is an empirical study that investigates and verifies the role played by user interaction in the process of creating highly competitive online content. Using online platforms, an unspecified number of users generate a variety of content, including text, software, animation, illustrations, and music. In recent years, this content has not only been held within the communities but also sold in the market. It is now common for some amateur content to gain market competitiveness equal to or better than professionally created content. We examine the influence of interaction between users on the quality and creation pace of content during the content creation process. To answer this question, we explored the Japanese light novel market and tested the mechanism of high-quality content generation on an online platform. Based on previous research, we divided the generation mechanism of content (novels) online by “the reason for producing competitive and high-quality works” and “the reason for maintaining the user’s creation pace.” Then, we built the four hypotheses and used statistical analysis to prove them. Regarding the “effects of UGC (user-generated content) in the art field” mentioned in the previous research, we found it was difficult to improve the quality of a novel through the exchanging of opinions between users, as the novels contain many subjective factors. On the other hand, our results showed that even before a novel was put onto the market, the platform could predict the future popularity of it. We also proved that qualitative information such as user comments could motivate human behavior, compared with quantitative information, such as evaluation rates. Finally, we found that the online evaluation rate had a positive effect on content selection, and that the comment feature had a positive effect on the writer’s creative pace. Thus, developing mutually complementary functions of a platform is an important managerial practice to promote interaction between users and generate competitive UGC.