To encourage more and higher-quality content, some knowledge platforms have started to pay contributors. It is unclear, however, whether and how such monetary incentives affect users’ contribution to non-paid (“free”) knowledge activities. Answering this question is important because consumers benefit from both paid and non-paid knowledge.

We study the effect of introducing monetary incentives for holding live talks on users’ contribution to the non-rewarded activity of answering questions on the same knowledge-sharing platform. We find that the launch of the paid feature creates a positive spillover effect on the quantity of free answers contributed by live hosts in the short run. We suggest reputation building is one plausible motivator for such spillover. Additional analyses reveal the spillover effect is negative for short-lived hosts in the long run, indicating possible crowding out of free contributions. The positive spillover effect for long-lived hosts lasts longer but is also reduced over time.

Our findings suggest that introducing monetary incentives can be a viable business model for knowledge platforms to stimulate user contributions in both the paid and related unpaid activities. Yet, platform owners should be cautious about the potential negative spillover after users stop contributing to the paid activity and develop effective strategies to maintain users’ long-term interests in the paid program.