  Community-based question answering (CQA) platforms are crowd-sourced services
for sharing user expertise on various topics, from mechanical repairs to
parenting. While they naturally build-in an online social network
infrastructure, they carry a very different purpose from Facebook-like social
networks, where users "hang-out" with their friends and tend to share more
personal information. It is unclear, thus, how the privacy concerns and their
correlation with user behavior in an online social network translate into a CQA
platform. This study analyzes one year of recorded traces from a mature CQA
platform to understand the association between users' privacy concerns as
manifested by their account settings and their activity in the platform. The
results show that privacy preference is correlated with behavior in the
community in terms of engagement, retention, accomplishments and deviance from
the norm. We find privacy-concerned users have higher qualitative and
quantitative contributions, show higher retention, report more abuses, have
higher perception on answer quality and have larger social circles. However, at
the same time, these users also exhibit more deviant behavior than the users
with public profiles.
