Personally controlled health management systems (PCHMS) often consist of multiple design features. Yet, they currently lack empirical evidence on how consumers use and engage with a PCHMS. An online prospective study was designed to investigate how 709 consumers used a web-based PCHMS to manage their physical and emotional wellbeing over five months. The web-based PCHMS, Healthy.me, was developed at UNSW and incorporates an untethered personal health record, consumer care pathways, forums, polls, diaries, and messaging links with healthcare professionals. The two PCHMS features that consumers used most frequently, found most useful, and engaging were the social features, i.e. forum and poll. Compared to participants who did not use any PCHMS social feature, those who used either the poll or the forum were 12.3% more likely to visit a healthcare professional (P=0.001) during the study. Social network analysis of forums revealed a spectrum of social interaction patterns-from question-and-answer structures to community discussions. This study provides a basis for understanding how a PCHMS can be used as a socially-driven intervention to influence consumers' health behaviours.