Reference group is an important factor influencing users’ purchase in the network communities. The reference group’s influences involve informative influence and normative influence, and users’ purchases are divided into the trial purchase and upgrade purchase. In different purchases, users have different product information, consumer experience, and purchase attitudes, making different responses to the reference group. Thus, a research model of reference groups’ influences on users’ purchase intentions from the perspective of trial purchase and upgrade purchase is constructed. The model and hypotheses are tested by analyzing 349 valid questionnaires. The results indicate that both informative and normative influences have significant positive effects on users’ trial purchase intentions. Informative influence has a significant positive effect on users’ upgrade intentions, while the normative influence on users’ upgrade purchase intentions is not significant. Both informative influence and normative influence have significant positive effects on trust in the product. Trust in the product has a significant positive effect on trial purchase intentions, but its effect on upgrade purchase intentions is not significant. Purchase involvement positively regulates the relationship between informative influence and trial purchase intentions and negatively regulates the relationship between informative influence and upgrade purchase intentions. The results further enrich the theoretical system of users’ purchase behaviors in a virtual environment. The research can also have important implications for network communities wishing to improve online marketing.

Consumer-to-consumer interaction is an important activity in network communities. Consumer-to-consumer interaction involves information interaction and social interaction, which greatly influences consumers’ experience and behaviors. The model of stimulus-organism-response (S-O-R) is usually applied to explain how environmental stimulus affects consumer behavior through the internal state. Thus, this research takes dissatisfactory consumers as the object, sets information interaction and social interaction as a stimulus, consumer knowledge and trust as an organism, and repetitive purchases as a response. It constructs a theoretical model that consumer-to-consumer interaction influences repetitive purchases through consumer knowledge and trust. In this study, the model and hypotheses were tested by analyzing 328 valid questionnaires. The results show that information interaction had a significant positive effect on consumer knowledge, while social interaction had no significant effect on consumer knowledge. Information interaction and social interaction each had significant positive effects on consumer trust. Consumer knowledge and trust each had significant positive effects on repetitive purchases. Consumer knowledge and trust played a partial mediating role between information interaction and repetitive purchase, respectively. Consumer knowledge had no mediating role between social interaction and repetitive purchases, while consumer trust played a complete mediating role between social interaction and repetitive purchases. The results revealed that the deep mechanism of consumer-to-consumer interaction’s influence on dissatisfactory consumers’ repetitive purchases in network communities further enriched consumers’ purchase behaviors, at least theoretically. This research also provided insights for network community marketing.