Many online question-and-answer (Q&A) communities have tried to motivate knowledge contribution through the implementation of gamification mechanisms. We know little, though, about the effectiveness of specific hierarchical privilege levels (a.k.a. “leveling up”) and non-hierarchical incentives (e.g., independent reputation gains and achievement badges) in promoting knowledge contribution. Drawing on goal-setting theory, expectancy-value theory, and other related theories, this study models how hierarchical privilege levels and non-hierarchical incentives serve as motivational goals stimulating continued knowledge contribution. By analyzing a rich dataset collected from an online Q&A platform, we find that closeness to the next hierarchical privilege level does, indeed, have a curvilinear relationship with continued knowledge contribution. Interestingly, non-hierarchical incentives, including reputation gains and granted badges, help to maintain continued knowledge contribution. Notably, user reputation diminishes the effects of both privilege levels and granted badges on future knowledge contribution. This implies that these gamification mechanisms, while potentially powerful for incentivizing user engagement in knowledge contribution, might not work as effectively for participants with already established reputations in the online community. This research provides theoretical and practical implications for motivating continued user knowledge contribution in online Q&A communities.