Understanding the processes and dynamics behind the collaborative construction of ontologies will enable the development of quality ontologies in distributed settings. In this paper, we investigate the collaborative processes behind ontology development with two Web-based modeling tools,
. We performed a quantitative analysis of user activity logs from both tools. This analysis sheds light on (i) the way people edit an ontology in collaborative settings, and (ii) the role of discussion activities in collaborative ontology development. To explore whether the ontology tool influences the collaboration processes, we conducted five investigations using the collaborative data from both tools and we found that users tend to collaborate in similar ways, even if the tools and their collaboration support differ. We believe these findings are valuable because they advance our understanding of collaboration processes in ontology development, and they can serve as a guide for developers of collaborative tools.