This paper compares two social media sites that aim to support patients to enhance self-management. The first site, PatientsLikeMe is a well established global site designed to allow peer-to-peer communication between people with similar conditions. The second, HealthShare, is a recently developed site for Australians described as "Australia's Social Health Network". The comparison conducted examines the purpose, ownership, and design of both sites as well as how the data they collect is used. Analysis highlights that PatientsLikeMe actively facilitates patient self-management, while HealthShare is revealed to be a professionally moderated health information portal presented as a social networking site. While the impetus for the development of PatientsLikeMe is clear, the motives underpinning HealthShare are less obvious. With increasing patient interest in connecting with, and sharing information with one another, awareness of the nature and motivations underpinning sites that provide these services is of increasing relevance.