Nowadays, online social networks (OSN) have become popular Internet platforms. While some of them are gathering an increasing number of users (e.g., Facebook), other OSN fail to maintain their user base (e.g., MySpace) and are confronted with a termination of their services. But what makes the difference between successful and less successful OSN? In literature, for instance, network effects, content related aspects and security mechanisms as well as the introduction of new features (e.g., Facebook’s “Places” or Bebo’s “Visitors Map”) are generally considered to be enablers of success for OSN. However, only little research has been done so far to empirically analyze the impact of new features on users’ communication activities and thus indirectly on the success of OSN. For this reason, our research examines whether the introduction of the central feature “Publisher” by Facebook caused a significant increase of users’ communication activities. In order to empirically investigate this question, we use a publicly available dataset of the Facebook New Orleans Network. Moreover, among others, we adapt and use the event study methodology to be able to account for trends in the time series of users’ communication activities. This leads to interesting results that do not support existing statements in literature.