people have experimented with different sorts of moo rooms that help control or channel discussion -- at the moment we have two room types at pennmoo that make various provisions, and we can import others when your combination of needs and comfort with the features becomes clear.
in the second floor of the classroom center -- the chestnut room -- lee-ellen marvin recently installed a moderated conference room. you can set the number of speakers at any give time, and others who try to speak are told that no one hears them. people who wish to speak type "request" and as the moderator "yields" someone who is finished (a speaker can also yield directly), the next person on queue is told they are able to speak. you are welcome to use this room, or we can help you make one with the same characeristics in a thematic classroom area.
i was at some virtual conference sessions at iath moo last weekend, and in that system the audience is in a balcony overlooking the panel of speakers. the panelists carried on a discussion among themselves, punctuated by questions from the audience that were typed into a queue and released one by one by a moderator. the audience, meanwhile, being in a separate room, carried on a second commentary that didn't interrupt the official proceedings. my feeling was that in fact there was almost too much focused analytic discussion going on -- i need to go back and read a transcript to get everything i could have out of the discussions. it played as some sort of written fugue that opened out in countless directions. i see some potential advantages -- it was more spontaneous and interactive than a formal written presentation (or even an e-mail exchange), yet you can keep a complete transcript and really go back to thinking aobut the conversation.
we also have a "generic classroom" where if you sit at one of the tables in the room, what you say is only heard by others sitting with you. it's one easy way to divide people up for smaller discussions in the same space. you can "speakup" and everyone at all the tables hears you. in fact, penncentral is currently a version of this room type. if you sit on the button, only those sitting with you will hear what you say.