Here's an experiment for someone more industrious than me to perform. This is a "mind experiment" to determine if podcasting is really dying out (as suggested by Jan Polet, and suspected by myself).
Get a list of RSS feeds with podcasts in them
Monitor daily (or pull out as many items in them)
Track podcasts and their update frequency
Graph out how long the period is between podcast updates
I suspect that podcasts have a high initial udpate freqency, then die off after some time that can be correlated (somehow) to number of listeners plus the podcaster's ability to pay the bandwidth bill. Also, I'd be interested in seeing the number of podcasts updated per day over a period of months. The graph of that would tell you if podcasting is dying, growing, or whatever.
Anyone up for this experiment?