This study investigates the influence of cash rewards on user engagement within online deal communities, exploring potential moderator effects of user reputation. Online deal communities, where users share discounts and promotions, are integral to e-commerce platforms, fostering consumer engagement and facilitating informed purchasing decisions. Motivation Crowding Theory provides a theoretical lens through which to understand how external incentives, such as cash rewards, may interact with intrinsic motivations and influence user behavior in these communities (Frey and Jegen 2001; Wu 2019). Drawing upon the Motivation Crowding Theory, which posits that external incentives can either complement or undermine intrinsic motivations, this research aims to elucidate the complex interplay between cash rewards, user engagement, and user reputation. By analyzing user activity data, this study aims to determine whether the introduction of cash rewards affects the frequency and quality of user-generated deal posts. Specifically, it examines whether cash rewards lead to an increase in the frequency of deal posts and whether they contribute to enhancements in the quality of these posts, as measured by factors such as helpfulness and attractiveness. Additionally, the research investigates whether user reputation moderates the impact of cash rewards on deal-posting behavior, exploring whether users with higher reputations respond differently to cash rewards compared to lower-reputation users. The findings of this research provide insights into the effectiveness of cash rewards as incentives for stimulating user engagement in online deal communities. Moreover, by considering the potential moderator effect of user reputation, the study offers a deeper understanding of how individual user characteristics may interact with incentive mechanisms to shape user behavior. Platform operators and community managers can leverage these insights to develop targeted strategies for incentivizing user engagement and fostering vibrant online communities. By recognizing the role of user reputation as a potential moderator, platforms can tailor their incentive structures to accommodate the diverse preferences and motivations of their user base. Overall, this research contributes to a broader understanding of the complex dynamics between incentive mechanisms, user engagement, and user characteristics in online communities. It emphasizes the importance of considering individual differences in user behavior when designing and implementing incentive programs to enhance community participation and interaction.