Doc Searls offers a slightly revisionist history of podcasting, giving us the background but omitting any mention of Adam Curry. A podcast, properly so-called, is an MP3 file the URL of which is distributed through an RSS feed. Curry’s first podcast (I think it’s this in 2004 but it might be earlier) software used the enclosure tag, first documented by Dave Winer in 2001. My own Ed Radio instead scraped the RSS feed for any reference to an MP3, which it then rendered in a playable SMIL file. I don’t remember Christopher Lydon being involved in the invention of podcasting at all, and his Radio Open Source doesn’t launch until 2005, though I guess Searls, Winer and David Weinberger knew him. Today, it is true, there is no single ‘podcast’ application, which is great. On the other hand, people have taken to calling any audio file a ‘podcast’, which is less great. It’s a podcast only if it is syndicated; otherwise, it’s just an audio file. See also iPodder, from 2005. The modern version of Ed Radio still runs to this day.