Watching the presidential debate on Wednesday, I was wondering whether debates might hurt the quality of voters' information because of "information crowding-out". People know that there is a debate, that they'll be able to learn information from the debate, and more importantly, that a lot of people are watching it.
Why would debate be more desirable than news pieces on CNN, in the NYT or on Wonkblog? Debates are a good focus point. If we believe the evidence on how opinions about debates are forming (i.e. that what matters is post-debate analysis by friends or TV channels), then we see that there is a "common value" component that make the debate more desirable as a source of information than newspaper articles or blog posts that you can't make sure people are reading at the same time as you are. There are multiple reasons why this can happen, say, social learning.
Now, I think it's also possible to say that debates are not the best source of information. The sources of information are biased and have an interest in manipulating their messages. Moreover, as we saw, the format has been quite restrictive if you look at all the issues that haven't been talked about: no talk about immigration, abortion, climate change, ...
The last piece of the puzzle is to say that watching the debate "prevents" you from getting other sources of news. Basically, you have other things you do. So you choose how much time you allocate to information. If you use up this time by watching the debate, that makes sense (second paragraph) but that's probably not good overall (third paragraph).