Honestly think stuff like this will replace the magic quadrant type of stuff that research/analyst firms focus on now.
Identify the key players like this, then one that shows their development over time (so, for podcasting, we'd see Dave Winer, Adam Curry through to the new enterprise stuff a la Serial), then the same identifies the stack of technologies and how they intersect, (libsyn through feedburner), and, where this could go.
Anyway, cool to see @danbenjamin on here.
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There's a few, popular, original podcasters missing here.
VC Puzzle
developer tea
Podfan
The State of Snapchat Analytics