Podcasting in Plain English

A short video if you fancy yourself a novice...

And, some reading:

• the article in which the term "Podcasting" was coined (The Guardian/Ben Hammersley)
• Podcasting's Reluctant Evangelist (Wired Magazine)
• The (infamous) Wikipedia entry on podcasting
  

These are the origins. To your mind, where is podcasting now? Take a look at the ITunes podcast charts and you see the usual (terrestrial) subjects up at the top. Is there a market for online-only radio, and what might online-only radio do -- and where can it go -- that broadcast can't?