Online health interactions (OHIs) can benefit patients, physicians, and society. However, little research has been conducted that studies the social value of OHIs for third-party patients who view previous OHIs concerning similar health issues to theirs. Drawing on the literature on social support and information uncertainty, this study established a theoretical model to explore the roles of treatment information, prevention information, and emotional support in determining information usefulness perceived by third-party patients, and whether such relationships are contingent on information uncertainty. The model was tested using “health questions and answers” textual data from 1,848 OHIs. The results indicate that prevention information and emotional support significantly improve information usefulness perceived by third-party patients. When the level of information uncertainty regarding physicians’ replies is high, the effect of treatment information is strengthened and the effect of emotional support is weakened, indicating both the bright and dark side of information uncertainty. This study has implications for practitioners and contributes to the literature on online health information, social support, information science, and information uncertainty.

在线健康互动（OHI）可以使患者，医生和社会受益。但是，很少有研究针对第三方患者的OHI的社会价值进行研究，这些患者查看过以前的OHI涉及与其相似的健康问题。该研究利用有关社会支持和信息不确定性的文献，建立了一个理论模型，以探索治疗信息，预防信息和情感支持在确定第三方患者感知的信息有用性中的作用，以及这种关系是否取决于信息。不确定。使用来自1,848个OHI的“健康问答”文本数据对模型进行了测试。结果表明，预防信息和情感支持显着提高了第三方患者对信息的实用性。当有关医生答复的信息不确定性水平很高时，治疗信息的效果会增强，而情感支持的效果会减弱，这表明信息不确定性的光明和黑暗面。这项研究对从业者具有影响，并为有关在线健康信息，社会支持，信息科学和信息不确定性的文献做出了贡献。