Dave Winer describes Bloggercon as follows:
BloggerCon is an unusual conference. We don't have speakers, panels or an audience. We do have discussions and sessions, and each session has a discussion leader.
Think of the discussion leader as a reporter who is creating a story with quotes from the people in the room. So, instead of having a panel with an audience we just have people. We feel this more accurately reflects what's going on. It's not uncommon for the audience at a conference to have more expertise than the people who are speaking.
The discussion leader is also the editor, so if he or she feels that a point has been made they must move on to the next point quickly. No droning, no filibusters, no repeating an idea over and over.
The discussion leader can also call on people, so stay awake, you might be the next person to speak!