A random conversation about John Cleese and training videos at Agile'08 on Tuesday reminded me that I wanted to post about something neat I saw at CAST'08. Everyone attending the talks had a red, a yellow, and a green card with a number on them (the same number for all three cards). If you wanted to start a new discussion thread during question time, you raised your green card; if you wanted to add something to the current thread, you raised your yellow card; and if you wanted to interrupt right now, you raised your red card. In the first two cases, the moderator wrote down your number so s/he could call on you when it was your turn; in the third case, you got to speak right away, but then your red card was taken away, so that you could only interrupt once per session. It seemed to work pretty well, and I'll use it in meetings of my own in future. Now, how do we redesign chat clients to achieve the same effect?