In a backlash against corporate branding and capitalism, a growing number of consumers are resisting current marketplace practices and big corporate brands. One particular form of this phenomenon is the emergence of anti-brand communities in social media. The current study, which surveyed a sample of 251 anti-brand community members on Facebook, provides a preliminary understanding of the characteristics and antecedents of anti-brand communities as a new platform for consumer empowerment and anti-brand activism. Findings suggest that consumers' engagement in online anti-brand communities, especially through social media, may be triggered by their negative experiences with employees, product quality, post-purchase service, and value/price. They are motivated, the results show, by seven primary factors: altruism, revenge, advice seeking, convenience, sympathy seeking, socialization, and the need to vent.