Didactical advantages of audience response systems (ARS) have been discussed extensively ever since they have been used in classes. However, conventional ARS bear some drawbacks, such as requiring specific hardware, generating costs (text messaging based and web service fees) and creating a dependency on external hosts. In this paper we present a browser-based ARS, which provides a platform-independent channel for the interaction between students and teachers. The authors provide a solution of an ARS for potentially large and spatially distributed classes, where the audience can provide feedback via PCs and mobile devices such as smart phones and tablets. The proposed system has been integrated into the e-learning system of the Vienna University of Economics and Business (WU), one of the largest business universities worldwide. The server side implementation of an ARS brings some challenges, such as the integration into an e-learning environment, the technical feasibility due to a broad variety of possible end user devices, and user acceptance issues. This paper documents the experiences and findings of the stepwise development and deployment in large classrooms. This resulted in an enhancement of the information policy with students and an optimization of the WLAN network settings. Finally, a new, unanticipated usage scenario emerged for mobile, browser-based response systems.