We present an analysis of the topics and research groups that participated in the ISMIR conference over the last 15 years, based on its proceedings. While we first investigate the topological changes of the co-authorship network as well as topics over time, we also identify groups of researchers, allowing us to investigate their evolution and topic dependence. Notably, we find that large groups last longer if they actively alter their membership. Furthermore, such groups tend to cover a wider selection of topics, suggesting that a change of members as well as of research topics increases their adaptability. In turn, smaller groups show the opposite behavior, persisting longer if their membership is altered minimally and focus on a smaller set of topics. Finally, by analyzing the effect of group size and lifespan on research impact, we observed that papers penned by medium sized and long lasting groups tend to have a citation advantage.