“…Second, "user," referring to health consumer (such as patient, family, caregiver, the public), is the participant and contributor of "platform," therein generating, sharing, receiving and using "information." From the perspective of user, studies on OHCs include user health information behavior (Chuang and Yang, 2010;Aarts et al, 2013;Zhang, 2016;Yan et al, 2016;Atanasova et al, 2017), user relationship network (Centola and van de Rijt, 2015;Zhao et al, 2016) and doctor-patient interaction (Wu and Lu, 2017;Atanasova et al, 2017;Zhang et al, 2019). As for user health information behavior in OHCs, Chuang and Yang (2010) explored the supportive interaction behavior in MedHelp alcoholism community through qualitative content analysis and identified three types of social support (informational, nurturant and Patient generated content (PGC): text, picture, link, video, etc.…”