Social event detection at MediaEval: a 3-year retrospect of tasks and results

This paper presents an overview of the Social Event Detection (SED) task that has been running as part of the MediaEval benchmarking activity for three consecutive years (2011 - 2013). The task has focused on various aspects of social event detection and retrieval and has attracted a significant number of participants. We discuss the evolution of the task and the datasets, we summarize the set of approaches ursued by participants and evaluate the overall collective progress that has been achieved.