Hi Pat,
Yes the live hangout can be a bit confusing if you've not taken part in one before. For future reference there is a Q&A App that runs in the browser from the streaming event which should appear on the right hand side of the video. If another app (like Showcase) has been enabled then you may have to click on the "boxes" icon on the top right of the video stream to select it.
This app lets the viewers submit questions, and upvote other people's questions. When they are selected (by Justin) it actually bookmarks the video so you can jump to the specific question in the recording that is published on Youtube afterwards.
Cheers,
Keith