To address issues of traditional modeling tools (installation, model versioning and lack of model repositories), Axellience has developed the first online UML modeling tool. In GenMyModel's beta-phase, the most requested feature was collaboration. Supporting collaborative modeling involves addressing classical concerns of CSCW. These issues are usually classified through core dimensions like awareness and artic-ulation work. We decided to focus our research on the most important dimension: awareness. Commercial modeling tools and research prototypes provide little support for awareness.To define the importance of awareness in modeling tools, we decided to study what awareness information is really required in collaborative modeling and to assess its importance according to articulation work types. To do this, we have implemented a basic collaboration system without constraint on articu-lation work. After a few months of use, we have identified three articu-lation work types present in more than 500 collaborative projects. This preliminary study allowed us to define awareness elements potentially needed for each articulation work type. As these elements are different for each articulation work type, we launched different surveys for each one of them. With these surveys, we have sorted awareness information by relevance according to articulation work types.