In large discussions, there seem to be two main ways in which people want to make contributions. The first of these is to introduce a new line of discussion on the current topic; the second is to respond to a recent comment by another speaker. These are both indicated by the same gesture: putting up your hand to get the attention of the facilitator of the meeting.
Most facilitators deal with this in a first-come-first-served fashion: this seems the fairest way of doing it. But, the lack of disambiguation between the two kinds of contributions leads to a seasick-inducing sway between different topics, as people several comments down the line begin their comment with “I’d like to return to what Jessica was saying a few minutes ago” or whatever. Sometimes people attempt to improvise a gesture/expression to convey that they want to speak next, usually in the form of a hand bobbing up and down and a desperate-for-a-piss expression on their face.
We need a more rational system for this. I propose (1) if you want to follow up the previous speaker immediately, then you put your hand up with a single finger extended; (2) if you have a general point, then you put your hand up with all fingers extended. Simples.