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.