Barcamps are conferences without predened content, often referred to as ad-hoc conferences or unconferences. Therefore, the outcomes of a barcamp are largely unknown before the event. This raises the question of participants' motivations to attend and contribute. To answer this question, we conducted an exploratory empirical study at the Barcamp Graz 2012. We applied a mixed-method approach: First we used a sociodemographic questionnaire (n=99) which allowed us to characterize the 'typical barcamper'. Second, we conducted qualitative interviews (n=10) to get a deeper
understanding of the participants' motivations to attend, expectations and the use of social media in that context. We identied three concepts, which could be deducted from the interviews: people, format and topics. We found that the motivation to attend and even a common identity is quite strongly based on these three factors. Furthermore, the results indicate that participants share a set of activities and methods by following the barcamp's inherent rules and make extensive use of social media.