Millions of people participate in online social media to exchange and share information. Presumably, such information exchange could improve decision making and provide instrumental benefits to the participants. However, to benefit from the information access provided by online social media, the participant will have to overcome the allure of <i>homophily</i>—which refers to the propensity to seek interactions with others of similar status (e.g., religion, education, income, occupation) or values (e.g., attitudes, beliefs, and aspirations). This research assesses the extent to which social media participants exhibit homophily (versus heterophily) in a unique context—virtual investment communities (VICs). We study the propensity of investors in seeking interactions with others with similar sentiments in VICs and identify theoretically important and meaningful conditions under which homophily is attenuated. To address this question, we used a discrete choice model to analyze 682,781 messages on Yahoo! Finance message boards for 29 Dow Jones stocks and assess how investors select a particular thread to respond. Our results revealed that, despite the benefits from heterophily, investors are not immune to the allure of homophily in interactions in VICs. The tendency to exhibit homophily is attenuated by an investor’s experience in VICs, the amount of information in the thread, but amplified by stock volatility. The paper discusses important implications for practice.
Virtual communities continue to play a greater role in social, political, and economic interactions. However, how users value information from these communities and how that affects their behavior and future expectations is not fully understood. Stock message boards provide an excellent setting to analyze these issues given the large user base and market uncertainty. Using data from 502 investor responses from a field experiment on one of the largest message board operators in South Korea, our analyses revealed that investors exhibit confirmation bias, whereby they preferentially treat messages that support their prior beliefs. This behavior is more pronounced for investors with higher perceived knowledge about the market and higher strength of belief (i.e., sentiment) toward a particular stock. We also find a negative interaction effect between the perceived knowledge and the strength of prior belief on confirmation bias. Those exhibiting confirmation bias are also more overconfident; as a result, they trade more actively and expect higher market returns than is warranted. Collectively, these results suggest that participation in virtual communities may not necessarily lead to superior financial returns.