In post-Web 2.0, the role of video has become increasingly important, both in e-learning and in blended learning systems. This article aims to identify how video annotation can help explore communication in teacher training. With the necessity to take into account the great diversity of pupils, collaborative work and online exchanges may help increase understanding of intercultural communication. Firstly, we begin with a presentation of collaborative video annotation to observe the place and the role of interaction in this system. Then, we seek to uncover elements of the design process in a design-based research project on Celluloid, a video annotation device through the description of two experiments: their contexts, the videos used, the consultation modalities and the annotation processes developed to increase interaction.