The Evolution and Diffusion of User Roles in Online Health Communities: A Social Support Perspective

Online Health Communities (OHCs) have become a major source of social support for people with health problems. Using a case study of an OHC among breast cancer survivors, we revealed the types of social support embedded in each post using text-mining techniques. Then we aggregated users' activities related to different types of social support and identified different roles that users play in an OHC via unsupervised machine learning techniques. By analyzing how users' roles change over time, we constructed a transition graph to illustrate the evolution of users' roles in the OHC. We also discovered that a user's reception of social support is correlated with the evolution of her role. In addition, by examining whom a user interacted with, we found evidence for "role diffusion"-users tend to adopt roles of her network neighbors. Our research has implications for OHC operators to manage and sustain an OHC.