As of 12-5-2005 7:00AM EST.
By 2003, web radio had existed for a decade, digital audio players had been on the market for several years, blogs and broadcasters frequently published MP3 audio online, and RSS file formats were widely used for summarizing or syndicating Web content.
The RSS enclosure element required for podcasts was created in version 0.92 of RSS, published in late 2000 by Userland Software's Dave Winer, spurred by a draft proposal from Tristan Louis and by conversations with Adam Curry, as well as a request from Harold Gilchrist, another user of Userland blogging software. The ability to send and receive enclosures was incorporated in Radio Userland, which included an RSS aggregator as well as a weblog editor. Winer and Curry discussed the enclosure feature as a way to avoid having to wait for downloads of large video or audio files, by pre-fetching them overnight. Gilchrist put the program to the test early, audioblogging in January 2002 and using the RSS enclosure feature with MP3 files by October 2002. However, few other aggregator developers adopted the enclosure feature until 2004. (Ironically, the rival RDF Site Summary syndication format already supported media resources implicitly, although applications rarely took advantage of the feature.)
In June 2003, Stephen Downes demonstrated aggregation and syndication of audio files using RSS in his Ed Radio application . Ed Radio scanned RSS feeds for MP3 files, collected them into a single feed, and made the result available as SMIL or Webjay audio feeds. In September 2003, Winer created an RSS-with-enclosures feed for his Harvard Berkman Center colleague Christopher Lydon, a former newspaper and television journalist and public radio radio talk show host. Since July, Lydon had been linking full-length MP3 interviews to his Berkman weblog, focusing on blogging itself and coverage of the coming 2004 U.S. presidential primary campaigns. In his announcement of Lydon's audio-enclosure feed, Winer challenged aggregator developers to "be a leader, give your users the tools to be among the first to get the benefit of these great interviews, and the new content that's sure to follow." Some did. In September 2003 Pete Prodoehl released a skin for the Amphetadesk aggregator that displayed enclosure links.
At the first Harvard BloggerCon conference, October 4-October 5, 2003, which Winer and friends organized, CDs of Lydon's interviews were distributed, and bloggers, developers and journalists discussed many aspects of online audio. After an audioblogging presentation by Harold Gilchrist, Kevin Marks demonstrated a script to download RSS enclosures and pass them to iTunes for transfer to an iPod. He said he had discussed the idea with Curry the previous day. Curry created a feed that he named "syncpod", which was used for testing by Marks, Werner Vogels and other developers at the conference, some of whom later became involved in open source podcatcher projects. Curry encouraged such development, as well as writing his RSS2iPod Applescript to move MP3 files from Radio Userland to iTunes. On October 12, 2003, he offered his blog readers the script as a way to "automagically update your iPod with any new mp3s that are downloaded to your Radio UserLand enclosures folder from enclosure aware RSS feeds." (Curry's conversations with Marks at Bloggercon had, he said, slipped his mind by December, 2005, but he was set straight -- after removing a reference to Marks from this Wikipedia entry.) Curry eventually called his script ipodder, at ipodder.org.
Possibly the first use of the term "podcasting" was as a synonym for audioblogging or weblog-based amateur radio in an article by Ben Hammersley in The Guardian on February 12, 2004 . The name wasn't widely adopted until that fall. In September, Dannie Gregoire used the term to describe the automatic download and synchronization idea that Curry had been promoting . Gregoire had also registered multiple domain names associated with podcasting. That usage was discovered and reported on by Curry, Winer and Dave Slusher of the Evil Genius Chronicles website.
That summer, development of command-line based tools also included Dave Slusher's "get_enclosures" script, Pete Prodoehl's "renko", and Ray Slakinski's "pyPodder." In September, iPodderX, the first desktop-based podcast client, was developed by August Trometer and Slakinski, using "pyPodder" as the starting point. Other clients, including iPodder Lemon (later renamed Juice), followed soon after.
By fall 2004, audio blogging had emerged from obscurity, associated with the then-hot iPod and pushed ahead by Curry's RSS2iPod script and the programs it inspired.
By October 2004, detailed how-to podcast articles had begun to appear online. In November 2004, liberated syndication libsyn launched what was apparently the first Podcast Service Provider, providing storage, bandwidth, and RSS creation tools.