About two years ago, it was a great game on the Internet to ask: What is a blogger? It's not easy to say what a blogger is, because bloggers use rather general purpose computer software, and general-purpose software can be used in many different ways.
Similarly, it's hard to say what's a podcaster, since podcasting is a medium that can be used in dozens of different ways. Still, if you listen to typical podcasts, you'll note a few common profiles; one of the most common is the person who just sits down at a microphone and talks. Some podcasters plan their material very carefully. Or they may just talk off the top of their heads, they do little editing, and they'll toss their casual, unscripted-sounding audio onto the web for us to hear.
So who's the first podcaster? Who's the first person who produced audio sounding like that, week in and week? I'd say you've got to go back to 1948, when Jean Shepherd started his twenty-some years of late night talks on the radio. You can listen to a lot of his material to see if you agree with me, a lot is online at the Shep Archives. (Caution, this site might be NSFC, as in “not safe for copyright law”.)
If you were any sort of counterculture person in the late 40s or 50s, chances are you listened to Shep and then next morning when you could manage to wake up, you discussed him with your friends. In retrospect, as you'll hear if you listen to some of his material, he really sounded like a podcaster.
Enough for today! I'll save my reminiscences about Shep for another time.