  As the world becomes more digitized and interconnected, information that was
once considered to be private such as one's health status is now being shared
publicly. To understand this new phenomenon better, it is crucial to study what
types of health information are being shared on social media and why, as well
as by whom. In this paper, we study the traits of users who share their
personal health and fitness related information on social media by analyzing
fitness status updates that MyFitnessPal users have shared via Twitter. We
investigate how certain features like user profile, fitness activity, and
fitness network in social media can potentially impact the long-term engagement
of fitness app users. We also discuss implications of our findings to achieve a
better retention of these users and to promote more sharing of their status
updates.
