  It is generally accepted as common wisdom that receiving social feedback is
helpful to (i) keep an individual engaged with a community and to (ii)
facilitate an individual's positive behavior change. However, quantitative data
on the effect of social feedback on continued engagement in an online health
community is scarce. In this work we apply Mahalanobis Distance Matching (MDM)
to demonstrate the importance of receiving feedback in the "loseit" weight loss
community on Reddit. Concretely we show that (i) even when correcting for
differences in word choice, users receiving more positive feedback on their
initial post are more likely to return in the future, and that (ii) there are
diminishing returns and social feedback on later posts is less important than
for the first post. We also give a description of the type of initial posts
that are more likely to attract this valuable social feedback. Though we cannot
yet argue about ultimate weight loss success or failure, we believe that
understanding the social dynamics underlying online health communities is an
important step to devise more effective interventions.
