The panel* discussion on The Use of Digital Backchannels in Shared Physical Spaces was a great discussion of the uses of backchannel at conferences and in classroom-type environments, as well as other shared environments.
The introductory remarks set the stage for what is possible with Bill Griswold describing the infrastructure and tools they have in place for backchannel in the classroom setting, and Liz Lawley extending that out to conferences and other settings where people might need / use a backchannel. Elizabeth Churchill made an important observation that "backchannel" has been around for millenia in verbal and physical clues as we talk in groups. And, given the topic, there was tons of conversation in the backchannel for this session -- including the backchannel being projected on the screen while people were talking.
My only at-the-mic question of the entire conference was centered around how acknowledging the backchannel changes the way a talk or presentation gets put together. Bill Griswold has talked about this quite a bit, based on his experience in the classroom (TA's monitoring the channel; students voting on important questions; saved logs for follow-up reminders). There is also potential utility for ongoing conversation if one records or otherwise saves the backchannel logs for later review / reminders. I decided to ask because of the conversation we were having in the backchannel.
There was also a lot of discussion about how the backchannel changes things for everyone who participates, even those who don't have access to it. An interesting thread discussed the idea that backchannel tends to shift power from the Person In Front Of The Room to the the community as a whole. Liz Lawley described a movement in faculty meetings to remove laptops, partially because laptops encourage the powerless (junior faculty) to ask questions of one another or people outside meetings when they are too intimidated to ask out loud.
I assume Liz will write up comments, and I see that Eric already has. And I have taken the action to suggest that Scoble figure out how to wire a campus with tablet PC's in order to facilitate the backchannelization of the educational experience.
* The panel was chaired by danah boyd (Berkley, Google, Misbehaving, Many2Many) with Joe McCarthy (recently left Intel Research), Elizabeth Churchill (FX Palo Alto), William Griswold (UCSD), Richard Hodkinson, Liz Lawley (RIT, Many2Many).