The skill set required for successfully conducting broadcast public interviews is not a relevant one for most people to have. But for those who are in the business, I wonder if there are any protocols, spoken or unspoken, against giving distracting verbal cues to show that, I guess, as the interviewer, you are indeed listening to the person you're interviewing.
Rebecca Costa demonstrates what I mean only too well. Scroll down to the interview with John Ross (12/17/10) and listen to the 40 seconds from 40:40-41:20. Notice (which will be an easy thing to do--the challenge would be to not notice) the five "uh huhs" Costa utters. I happened to check the media player during that time period, but it's something she does with great frequency. Richard Spencer also does it to the point of distraction.
I understand that non-words are a difficult thing for people to cut out of their speech patterns and I don't mean to be acerbic in drawing attention to it. But in these cases, it simply requires one person to be quiet while the other person is speaking. With minimal effort, it would presumably be an easy and beneficial thing to do.