Existing constructs for privacy concerns and behaviors do not adequately model deviations between user attitudes and behaviors. Although a number of studies have examined supposed deviations from rationality by online users, true explanations for these behaviors may lie in factors not previously addressed in privacy concern constructs. In particular, privacy attitudes and behavioral changes over time have not been examined within the context of an empirical study. This paper presents the results of an Agile, sprint-based longitudinal study of Social Media users conducted over a two year period between April of 2009 and March of 2011. This study combined concepts drawn from Privacy Regulation Theory with the constructs of the Internet Users' Information and Privacy Concern model to create a series of online surveys that examined changes of Social Media privacy attitudes and self-reported behaviors over time. The main findings of this study are that, over a two year period between 2009 and 2011, respondents' privacy concerns and distrust of Social Media Sites increased significantly, while their disclosure of personal information and willingness to connect with new online friends decreased significantly. Further qualitative interviews of selected respondents identified these changes as emblematic of users developing ad-hoc risk mitigation strategies to address privacy threats.