There are good reasons to pay attention to news and public affairs (civic responsibility, your job requires knowing what's happening, conversational material, etc.). There are good reasons to not pay attention (busy schedule, hate the partisanship, worried about missing the next Dancing with American Idol episode, etc.).
How much attention is enough?
If you read the scholarship on political knowledge, you might come away thinking there is a magic amount that everyone should know, a certain degree of attention everyone should have. Carefully read the literature, though, and you find the nuances: people learn what they need to know based on their jobs, their social situations, their time and resources.
Scholars tend to ask the same kinds of questions to tap political knowledge. We do this in part because they seem to work from study to study and it allows us to compare -- more or less -- our finding with other studies. It all gets into the reliability and validity of our measures that, if established by other research, frees us to get at the more substantive analyses. In other words -- get past the method stuff and get to the fun results. Sometimes a study will come along that challenges the status quo of how to measure knowledge. These are acknowledged quickly by most scholars and then they move on to, yes, studying it the same way other people have done over the years.
It may be time to reconsider our measures.
So back to my question above: How much attention is attention? We know that media exposure is a lousy measure, that how much someone attends to a medium is a more fair, more valid, and at times more reliable measure. Perhaps we need individual-specific attention measures. Is a "high" attention for one person the same as a "high" for another? And do they have the same consequences? We have to tie together exposure, attention, and some other factor -- not sure what -- to get at the changes in the media landscape. One answer may be elite versus middle-brow versus low-brow sources of news.
Is high attention to Bill O'Reilly the same as high attention to NewsHour? Probably not, but they'd go down at the same in a research situation (depending on how you scale it).
But trying to scale the kinds of content people consume, that's rife with problems. Should I score Fox News lower than CNN? No, I don't think so. People versus New Yorker magazines? Yep, that's easy. It's TV where we get into trouble, and we're probably going to have to drill down to the individual program level to get at some of this, and that's a whole different problem when it comes to survey (versus experimental) research.