When you enter the auditorium you land in a row rather than a room. You can chat with others in your row in the row tab below the chat pane. You can move to other chairs in other rows by clicking on the seat map button. Text from the stage is seen by everyone, but only your row sees the row text.
When in event is in progress, a "Something to Say?" button appears on the stage. With this, you can send questions to the stage to be asked by the guest.