Because of the limitation of time and resources, health professionals are often not able to provide support for consumers via personal communication. Consumers are increasingly active in managing their own health. E-word-of-mouth (eWOM), or consumer-generated content, on health social networking sites (SNSs) provides a new opportunity for health communication tailored to consumers' personal needs. Using netnography, a well structured internet-based ethonography, we analyze discussion threads posted to an obesity support group on a popular health SNS based in the US. We classify e-group members as support seekers and providers. Our results identify two major features of eWOM on health SNSs that facilitate tailored health communication. First, eWOM on health SNSs provides the types of support (informational and emotional) that help support seekers actively cope with heath-related problems and strains. Second, eWOM on health SNSs contains massages rich with personal experiences of support providers that offer solutions for problems that support seekers face in everyday situations. As support seekers participate in SNSs, their opportunity for learning means that they can become ‘information elite’, evolving from support seekers to support providers. We discuss important implications for policymakers and marketers for learning from and participating in eWOM on health SNSs. Copyright © 2011 John Wiley & Sons, Ltd.