Understanding privacy implications of access control policies is a
complex task for the users of social network systems. Users need
tool support to articulate on access scenarios and perform policy
analysis. In this work, we develop a prototypical tool for reflective
policy assessment (RPA) – a process in which a user examines her
profile from the viewpoint of another user in her extended
neighborhood in the social graph. Since an unrestricted view of
one's extended neighborhood may compromise the privacy of
others, our visualization tool approximates the extended
neighborhood of a user in such a way that policy assessment can
still be conducted in a meaningful manner, while the privacy of
other users is preserved. We verify the utility and usability of our
tool in a within-subject user study.