The first purpose of this paper is to provide an overview of the most commonly-used awareness mechanisms, namely, What You See Is What I See, telepointers, multi-user scrollbars, radar views and distortion-oriented views. These mechanisms were derived from researchers' intuition, without prior experimental investigation of what awareness information end-users really need. This research utilised a completely user-centered approach to determine relevant awareness mechanisms. The novelty of this approach is in the use of usability experiments to identify awareness mechanisms. In addition to the illustration of several innovative mechanisms, this research has also successfully differentiated the importance of different awareness information in maintaining group awareness. The significance of different awareness information has been thoroughly compared. These results help designers to know which information must be provided to all team members.