As in other domains, there has been unprecedented growth in diabetesrelated social media in the past decade. Although there is not yet enough evidence for the clinical benefits of patient-to-patient dialogue using emergent social media, patient empowerment through easier access to information has been proven to foster healthy lifestyles, and to delay or even prevent progression of secondary illnesses. In the design of diabetes-related social media, we need access to personal health data for modelling the core disease-related characteristics of the user. We discuss design aspects of mobile peer support, including acquisition of personal health data, and design artefacts for a healthcare recommender system. We also explore mentoring models as a tool for managing the transient relationships among peers with diabetes. Intermediate results suggest acquiring health data for modelling patients' health status is feasible for implementing a personalized and mobile peer-support system.