On January 1, 2010, the Shenzhen Stock Exchange (SZSE) in China launched an online interactive platform named “Hudongyi.” This platform enables individual investors to communicate directly with executives of firms listed on the SZSE, under the supervision of the SZSE, thereby providing a quasi-natural experiment to study the impact of individual investors on corporate governance. Employing a difference-in-differences design, we document that the investor-firm interactions on Hudongyi deter real earnings management by firms listed on the SZSE through reducing information asymmetry and raising reputational costs. This effect varies with posting specificity, interaction effectiveness, and firm features. These findings suggest that individual investors can effectively engage in corporate governance when their right to speak up is facilitated by proper technology and regulatory scrutiny.