One of the tweets that John chose to retweet was a reference to Joan Rivers leaving Johnny Carson - https://twitter.com/#!/dr_mind_bender/status/203903404953714...

It seems that he thinks of podcasts like late night TV - where the audience is just an abstract statistic.

In Dan's response above he makes a reference to drive-time radio talk shows and the sense of relationship (albeit one-way) that comes from that medium. He sees his audience as individual people whereas John only sees the audience as a revenue source.