I listened to part of yesterday's YouTube/CNN Presidential Political Debate last night and found it refreshing - there's a good summary of the Debate in KnowMoreMedia.com - YouTube Puts “You” in Democratic Debate.

I would think with YouTube involved, the metrics part - deciding what viewers are responding to - would be easier and more exact; not sure that's the case as the debate was viewed on CNN, not YouTube - but there are plenty of clips, such as those shown here, that are being measured for number of plays, number of backlinks, etc - and that information should be interesting to study more closely.