While the body of privacy research on online social networks has been growing over the past several years, privacy problems emerged from the dynamism inherent in the launch of new features or interfaces have not been widely discussed. Drawing on the grounded theory approach, we aim to fill this gap by investigating the trigger conditions under which users may perceive the introduction of a new IT artifact as privacy threats. With the specific case of the New Profile introduced by Facebook, we conducted a content analysis of user responses posted on the official blog of Facebook. Results can be constructed as a process model including two stages. The first stage of the model presented four broad categories of trigger conditions of privacy concerns-information processing, increased accessibility, intrusion, and loss of control. The second stage describes three types of outcomes, including psychological outcomes, behavior outcomes, and suggested privacy mechanisms.