[dhosek]

A lot of in-person interaction for groups is just not possible with most (all?) conferencing solutions, e.g., sidebar discussions. Some of this can be handled through texts (which are an occasional solution in in-person meetings as well—in grad school, I was occasionally in group texts mocking the person speaking to our class), although there's the danger that messages might pop up inopportunely while screen sharing (this happened to a co-worker of my wife's during a presentation once).

And of course, there's always this: "Leaving your mic on is the new reply-all."

[rumcajz]

Interesting problem. It would be partly solved by the look-and-look-back protocol, because then it's obvious that you are speaking to a single person. But then, it could still happen that you accidentally avert your gaze and drop back to the common chatroom, making what you are saying audible to everyone.