What Drove Success at the 15th Video Browser Showdown? A Comprehensive Interaction-Logging Analysis

In 2026, the Multimedia Modeling conference in Prague hosted the fifteenth edition of the Video Browser Showdown (VBS) competition. Yet, for the first time, two participating systems implemented full-scale interaction logging frameworks, enabling a detailed analysis of the search process beyond traditional score-based evaluation. In this paper, both systems are introduced and described with a focus on their user interactions. To enable compact presentation and analysis of logs, all interaction types are further grouped into more abstract events, forming an interaction taxonomy hierarchy. Finally, we reveal the applied search strategies and analyze which factors drive success and failure. The results reveal a clear dominance of iterative, high-frequency text query reformulation with result set inspection, leveraging the power of modern CLIP-based models across most competition categories. In around 10% of cases, users also relied on advanced system features to achieve good performance at VBS, mostly on challenging homogeneous datasets.