well, the hour flew by and in spite of my initial concerns - if not cynicism about the medium, it was surprisingly effective.
Signal strength varied and so one person never really succeeded in joining us, one only heard intermittently and a third had only chat facility though she could hear and see the screen: the other three managed to have conversations chiefly about the assignment criteria, how to develop a wiki and latterly about developing trust in teams.
In the last instance, the team members (including the one who could only add chat input) gave some good ideas to the person with the issue - so that it became a bit of an "action learning" session.
The issue was a central one to the module: development of trust in a virtual/dispersed team: especially where there are ancient and deep rooted tribal differences.
Feedback was very positive - I felt there was real learning and sharing: the voice and webcam helps to create a more grounded kind of contact than just chat. And that's what students said too."Like being with someone in the classroom"
Great fun, very useful, will definitely do it again!