Gopalsamy, Rahul, et al. "Engagement as a driver of growth of online health forums: observational study." Journal of Medical Internet Research 19.8 (2017): e7249.

Emerging research suggests that the growth of online communities is driven by network effects, where increased user-generated content enhances the community's value. The metric engagement capacity measures how well users can engage each other to generate content, while quantity engagement value quantifies communication on the platform. In the context of online health forums (OHFs), tracking engagement could be crucial for managers to harness network effects and predict the forum's future success.