I am posting this here because I couldn't successfully leave a comment to the post over on BloggerCon.org.
First of all thank-you for BloggerCon to the organizers and the participants. This is my kind of conference.
I have the following "thinking out loud" ideas for future BCs:
i) have a technographer/live blogger blog the session live and have this projected up on the screen (I volunteer to do this for one session at the next one)
ii) have a formal IRC person monitor the IRC chat and inform the DL of the state of the IRC periodically (again I volunteer to do this for one session at the next one and again this should be up on the big screen for all to see)
iii) try a non theatre-style room, i.e. one with a huge round table or several round tables (inspired by Ed Cone's suggestion at the closing session).