If we look at the media perspectives podcasts give, I've noticed an interesting phenomena in two podcasts recently, the two are: the sam harris podcast and naval periscope.
It seems to me that these two act as aggregators. Which means they have a crowd of people which contribute questions which act as a kind of filter to increase the quality of content.
The questions is how good this models scales and how valueable is it to the people consuming the media its related to - the podcast. I think its a very good strategy to increase engagement and to circle even more attention towards the creator of the medium.