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'''Podcasting''' is a term coined in 2004 when the use of [[RSS_(file_format) |RSS]] [[Web_syndication |syndication]] technologies became popular for distributing audio content for listening on mobile devices and personal computers. A podcast is a [[web feed]] of audio or video files placed on the Internet for anyone to subscribe to. Podcasters' websites also may offer direct download of their files, but the subscription feed of automatically delivered new content is what distinguishes a podcast from a simple download or real-time [[streaming media|streaming]] (see below).

While the name was primarily associated with audio subscriptions in 2004, the [[RSS (file format)| RSS]] enclosure syndication technique had been used with video files since 2001, before portable video players were widely available. In fact, any file with a [[URL]], including still images and text, can be delivered as an enclosure. 

Use of "podcast" to describe both audio and video feeds seemed natural to some users, while others preferred to reserve the word for audio and coin new terms for video subscriptions. Other "pod-" derived neologisms include "podcasters" for individuals or organizations offering feeds, and "[[podcatchers]]" for special RSS [[news aggregators|aggregators]] with the ability to transfer the files to media player software or hardware.

== Podcasting versus broadcasting and streaming ==
Subscribing to podcasts allows a user to collect programs from a variety of sources for listening or viewing offline at whatever time and place is convenient to the user. In contrast, traditional broadcasting provides only one source at a time, and the time is broadcaster-specified. 

"[[streaming media|Streaming]]" files from the Internet can remove the specified-time restriction, but still offers only one source at a time, and requires the user to be connected to the Internet while playing the files. The ability to "[[news aggregator |aggregate]]" programs from multiple sources is a major part of the attraction of podcast-listening.

Unlike podcasts, streaming also can be used to broadcast live events over the Internet at the moment they occur.

Although streamed programs, like broadcast radio signals, can be recorded or captured by the receiver, their transient nature distinguishes them from podcast episodes, which arrive already in archived form.  (This difference may make a podcast legally distinct from a [[webcast]] or streamed media file.)

== Name ==

"Podcasting" is a [[portmanteau]] word coined in 2004 (see "History" below), that combined two words: "[[iPod]]" and "[[broadcasting]]."

Neither podcasting nor listening to podcasts requires an iPod or other portable player, and no over-the-air broadcasting is required. The name association came about simply because [[Apple Computer]]'s iPod was the best-selling portable digital audio player when podcasting began and was used by early practitioners.

However, the use of the "pod" name in 2004 probably played a part <ref>Gruber, John. "[http://daringfireball.net/2005/07/podcast_pocket Is That a Podcast in Your Pocket?]", speculates that the word itself played a significant part in Apple's decision to add podcasting support to iTunes.</ref> in Apple's development of podcasting products and services in 2005, further linking the device and the activity in the news media. 

The editors of the [[New Oxford American Dictionary]] declared "podcasting" the 2005 word of the year in December, defining the term as "a digital recording of a radio broadcast or similar program, made available on the Internet for downloading to a personal audio player".<ref>Oxford University Press, [[2005-12-05]]  [http://www.prnewswire.com/cgi-bin/stories.prl?ACCT=104&STORY=/www/story/12-05-2005/0004228195&EDATE= Podcast is word of the year]</ref>

From the beginning various writers suggested other names or alternative interpretations of the letters "P-O-D."  Technology writer [[Doc Searls]] had proposed "Personal Option Digital" in September, 2004. <ref>Doc Searls [[2005-09-28]] [http://www.itgarage.com/node/462 DIY Radio with PODcasting]</ref> The "Personal On Demand" interpretation was in  international circulation as early as October 2004.<ref>[[2004-10-05]] [http://wikilab.net/archivi/2004/10/05/podcasting/ Podcasting]</ref> In July 2005, Microsoft blogger [[Robert Scoble]] mentioned that interpretation while countering reports that his company was pushing the word "blogcasting" to avoid mentioning an Apple product.<ref>Robert Scoble  [[2005-07-12]] [http://radio.weblogs.com/0001011/2005/07/12.html#a10602 Blogger gives incorrect data about podcasting at Microsoft]</ref> "Blogcasting" also implied content based on, or similar in format to, [[blogs]], which was not always the case.  
 
Another Apple rival in the portable audio and video market, [[Creative Technology]], began using the "Personal On Demand" interpretation, while offering its own "Zencasts."<ref>[http://www.zencast.com/about/ Creative "Zencast" Podcasts]</ref>  

Other terms have been suggested, but had shortcomings --  "[[audioblogging]]," "audio magazines" and "webcasting" could describe other forms of media distribution, and "rsscasting," would be difficult to pronounce.  

Podcasting as a medium was first associated with, but never limited to, audio data. As use of RSS enclosures for video spread in 2005, podcasting of video data was called, among other things, "video blogging", "video podcasting", "[[vlog]]ging", "[[vodcast]]ing", or "vidcasting".

== Mechanics ==

The publish/subscribe model of podcasting is a version of [[push technology]], in that the information provider chooses which files to offer in a feed and the subscriber chooses among available feed channels. While the user is not "pulling" individual files from the Web, there is a strong "pull" aspect in that the receiver is free to subscribe to (or unsubscribe from) a vast array of channels. Earlier Internet "push" services (e.g., [[PointCast (dotcom)|PointCast]]) allowed a much more limited selection of content.

Podcasting is an automatic mechanism by which multimedia [[computer file]]s are transferred from a [[server]] to a [[client (computing)|client]] which pulls down XML files containing the Internet addresses of the media files. In general, these files contain [[audio]] or [[video]], but also could be [[digital image|images]], text, [[Portable Document Format|PDF]], or any file type.

A ''podcast'' is generally analogous to a recorded television or radio series. 

The content provider begins by making a file (for example, an [[MP3]] audio file) available on the Internet.  This is usually done by posting the file on a publicly-available [[webserver]]; however, [[BitTorrent]] trackers also have been used, and it is not technically necessary that the file be publicly accessible.  The only requirement is that the file be accessible through some known [[Uniform Resource Identifier|URI]] (a general-purpose Internet [[address]]).  This file is often referred to as one ''episode'' of a podcast.

The content provider then acknowledges the existence of that file by referencing it in another file known as the ''feed''.  The feed is a machine-readable list of the URIs by which episodes of the show may be accessed.  This list is usually published in [[Really Simple Syndication|RSS]] format, which provides other information, such as publish dates, titles, and accompanying text descriptions of the series and each of its episodes. The feed may contain entries for all episodes in the series, but is typically limited to a short list of the most recent episodes, as is the case with many news feeds.

The content provider posts the feed to a known location on a webserver.  (Unlike the episode file itself, the feed is published to a webserver, usually not by other means.)  The location at which the feed is posted is expected to be permanent.  This location is known as the ''feed URI'' (or, perhaps more often, ''feed [[URL]]'').  The content provider makes this feed URI known to the intended audience.

A consumer enters this feed URI into a software program called a ''[[podcatcher]]'' or ''[[news aggregator|aggregator]]'' (the former term is specific to podcasting while the latter is general to all programs which collect news from feeds).  This program retrieves and processes data from the feed URI.

A podcatcher is usually an always-on program which starts when the computer is started and runs in the background.  It manages a set of feed URIs added by the user and downloads each at a specified interval, such as every two hours.  If the feed data has substantively changed from when it was previously checked (or if the feed was just added to the podcatcher's list), the program determines the location of the most recent episode and automatically downloads it to the user's computer.  Some podcatchers, such as [[iTunes]], also automatically make the newly downloaded episodes available to a user's portable media player.  (This is only the typical behavior of a podcatcher; some podcatchers behave&mdash;or can be set to behave&mdash;differently.)

The downloaded episodes can then be played, replayed, or archived as with any other computer file.

==History==
===Initial development===

What makes podcasting unique from other digital audio and video delivery is the use of syndication feed enclosures. The concept was proposed in a draft by [[Tristan Louis]] in October, 2000<ref>Louis, Tristan, [[2000-10-13]]. ''[http://groups.yahoo.com/group/syndication/message/698 Suggestion for RSS 0.92 specification]''</ref>, and implemented in somewhat different form by [[Dave Winer]], a software developer and an author of the [[RSS (file format)|RSS format]]. Winer had discussed the concept, also in October 2000, with [[Adam Curry]]<ref>Curry, Adam, [[2000-10-27]] [http://adamcurry.editthispage.com/broadband/ The Bandwidth Issue]; server discontinued by Userland, late 2005.</ref>, a user of his software, as well as having other customer requests for [[audioblogging]] features. He included the new functionality in RSS 0.92<ref>Winer, Dave, [[2000-12-25]] ''[http://backend.userland.com/rss092 RSS 0.92 Specification]''</ref>, by defining a new element<ref>Winer, Dave, [[2000-12-27]] ''Scripting News:  [http://www.scripting.com/2000/12/27.html Heads-up, I'm working on new features for RSS that build on 0.91. Calling it 0.92...]''</ref> called "enclosure"<ref>Winer, Dave, [[2000-10-31]] ''[http://davenet.scripting.com/2000/10/31/virtualBandwidth Virtual Bandwidth]''; and [[2001-01-11]] ''[http://www.thetwowayweb.com/payloadsforrss Payloads for RSS].''</ref>, which would simply pass the address of a media file to the RSS aggregator. Winer demonstrated how the feature would work by enclosing a Grateful Dead song in his [http://scripting.com Scripting News] weblog on January 11th, 2001<ref>Winer, Dave, [[2001-01-11]] ''Scripting News:  [http://www.scripting.com/2001/01/11.html Tonight's song on the Grateful Dead audio weblog is Truckin...]''</ref>. 

For its first two years, the enclosure element had relatively few users. Winer's company incorporated the new feature in its weblogging product, [[Radio Userland|Radio Userland]], the program favored by [[Adam Curry| Curry]], audioblogger [[Harold Gilchrist]] and others. Since  [[Radio Userland|Radio Userland]] had a built-in aggregator, it provided both the "send" and "receive" components of what was then called [[audioblogging]]<ref>Curry, Adam, [[2002-10-21]] ''UserNum 1014: [http://radio.weblogs.com/0001014/2002/10/21.html#a2427 Cool to hear my own audio-blog...]''</ref><ref>Gilchrist, Harold [[2002-10-27]] ''Audioblog/Mobileblogging News [http://radio.weblogs.com/0100368/2002/10/27.html this morning I'm experimenting with producing an audioblogging show...]</ref>. All that was needed for "podcasting" was a way to automatically move audio files from Radio Userland's download folder to an audio player (either software or hardware) -- along with enough compelling audio to make such automation worth the trouble.

While few developers of RSS-capable blogging software or aggregators made use of the enclosure element, in [[June]] [[2003]], [[Stephen Downes]] demonstrated aggregation and syndication of audio files in his Ed Radio application<ref>Downes, Stephen, June, [[2003]] ''[http://www.downes.ca/ed_radio.htm Ed Radio]''</ref>. Ed Radio scanned RSS feeds for MP3 files, collected them into a single feed, and made the result available as [[Synchronized Multimedia Integration Language|SMIL]] or [http://webjay.org Webjay] audio feeds. 

In September 2003, Winer created a special RSS-with-enclosures feed for his [[Harvard_Law_School| Harvard Berkman Center]] colleague [[Christopher Lydon]]'s weblog, which previously had a text-only RSS feed. Lydon, a former [[New York Times]] reporter and [[NPR]] talkshow host, had posted 25 in-depth interviews with bloggers, futurists and political figures, which Winer gradually released to the feed<ref>Lydon, Chris [[2003]] ''[http://blogs.law.harvard.edu/lydon/allInterviews Chris Lydon Interviews...]''</ref>. Announcing the feed in his weblog, Winer challenged other aggregator developers to support this new form of content and provide enclosure support. Not long after, Pete Prodoehl released a skin for the [http://www.disobey.com/amphetadesk/ Amphetadesk] aggregator that displayed enclosure links<ref>Prodoehl, Peter, [[2003-09-24]] RasterWeb:  [http://rasterweb.net/raster/2003/09/24/20030924083605/ Enclose This!]</ref>.

A month later, in [[October]] of [[2003]], Winer and friends organized the first [[Bloggercon]] weblogger conference at [[Harvard_Law_School| Berkman Center]].  CDs of Lydon's interviews were distributed as an example of the high-quality MP3 content enclosures could deliver<ref>Andrew Grumet, 2005. [http://grumet.net/weblog/archives/2005/04/26/a_slice_of_podcasting_history.html A slice of podcasting history].</ref>;  Bob Doyle demonstrated the portable studio he helped Lydon develop<ref>[http://media.skybuilders.com/lydon/studio.html Christopher Lydon's Portable Web Studio for Blogradio Productions]</ref>; [[Harold Gilchrist]] presented a history of audioblogging, including Curry's early role, and [[Kevin Marks]] demonstrated a script to download RSS enclosures and pass them to iTunes for transfer to an iPod<ref>Marks, Kevin. October [[2003]] [http://homepage.mac.com/kevinmarks/audiopod.m4v video excerpt of Marks's demo (MPEG-4)] [http://cyber.law.harvard.edu/ml/output.pl/35512/stream/temp.ram Real stream of full Audioblogging session (start 48 minutes in)] [http://epeus.blogspot.com/2003_10_01_epeus_archive.html#106527364652597310 blog post]</ref>. Curry and Marks discussed collaborating. After the conference, Curry offered his blog readers an RSStoiPod<ref>Curry, Adam, [[2003-10-12]] [http://radio.weblogs.com/0001014/2003/10/12.html#a4604 RSS2iPod]</ref> script that moved mp3 files from   Userland Radio to iTunes, and encouraged other developers to build on the idea. The iPodder idea was picked up by multiple developer groups. While many of the early efforts remained command-line based, the first podcasting client with a user interface was [http://iPodderX.com iPodderX], developed by August Trometer and Ray Slakinski and released in mid-September, 2004. Shortly thereafter, another group (iSpider) rebranded their software as iPodder and released it under that name as Free Software.

The term "podcasting" was one of several terms for portable listening to audioblogs suggested by [[Ben Hammersley]] in ''[[The Guardian]]'' on [[February 12]] [[2004]], referring to Lydon's interview programs ("...all the ingredients are there for a new boom in amateur radio. But what to call it? Audioblogging? Podcasting? GuerillaMedia?")<ref>Hammersley, Ben. 2004.  "[http://www.guardian.co.uk/online/story/0,3605,1145689,00.html Audible revolution]." In ''The Guardian'', [[2004-02-12]].</ref>. In [[September]] of [[2004]], Dannie Gregoire also used the term to describe the automatic download<ref>Gregoire, Dannie J. 2004. "[http://groups.yahoo.com/group/ipodder-dev/message/41 How to handle getting past episodes?]" In the ''ipodder-dev'' mailing list, Thu, [[2004-09-16]].</ref> and synchronization of audio content; he also registered several 'podcast' related domains (e.g. [http://www.podcast.net podcast.net]). The use of 'podcast' by Gregoire was picked up by podcasting evangelists such as Dave Slusher<ref>David Slusher's [http://www.evilgeniuschronicles.org/wordpress/category/technology/computers/podcasting/ Podcasts].</ref>, Winer and Curry, and entered common usage.

In [[September]] [[2004]], Curry launched an [http://groups.yahoo.com/group/ipodder-dev/messages/1 ipodder-dev mailing list],  then [[Slashdot]] had a 100+ message discussion<ref>Shashdot et al, 2004. [http://apple.slashdot.org/article.pl?sid=04/09/15/1414206&tid=176&tid=180&tid=182&tid=3 Time-shifting for the iPod].</ref>, bringing even more attention to the [[ipodder]]  developer projects in progress at [[SourceForge]]. By [[October]] [[2004]], detailed how-to podcast articles<ref>Torrone, Phillip. 2004. "[http://www.engadget.com/entry/5843952395227141/ How-To: Podcasting]." In ''Engadget'', [[2004-10-05]].</ref> had begun to appear online, and  a month later, liberated syndication [[libsyn]] launched what was apparently the first Podcast Service Provider, offering storage, bandwidth, and RSS creation tools.

In Feburary 2005, Australians Cameron Reilly and Mick Stanic started what was the first Commercial Podcast Network, [http://www.thepodcastnetwork.com/ The Podcast network]. Reilly described his vision for the network to be the Time Warner of New media. In November of 2005, they signed a Network wide sponsorship deal with Motorola.

===Precursor===
Prior to the Internet, in the 1970's, RCS, [[Radio Computing Services]], provided music and talk related software to radio stations in a digital format. 
Prior to online music digital distribution, the midi format as well as the [[Mbone]], Multicast Network was used to distribute audio and video files.  The MBone was a multicast network over the Internet used primarily by educational and research institutes, but there were audio talk programs<ref>Miles, Peggy and Dean Sakai, Internet Age Broadcaster I and II, National Association of Broadcasters.</ref>. 

Many other jukeboxes and websites in the mid 1990's provided a system for sorting and selecting music or audio files, talk, segue announcements of different digtal formats.  There were a few websites that provided audio subscription services. 

The development of downloaded music did not reach a critical mass until the launch of [[Napster]], another system of aggregating music, but without the subscription services provided by podcasting or video blogging aggregation client or system software.

Independent of the development of podcasting via RSS, a portable player and music download system had been developed at [[Compaq]] Research as early as [[1999]] or [[2000]]. Called PocketDJ, it would have been launched as a service for the [[Personal_Jukebox#PocketDJ_-_The_original_idea_of_Podcasting.3F|Personal Jukebox]] or a successor, the first hard-disk based MP3-player.

A fully-conceived precursor to podcasting came from another early MP3 player manufacturer. To supply content for its players the I2Go company, makers of the eGo player, introduced a digital news service called MyAudio2Go.com that created daily audio news feeds users could dowloaded to the eGo or any other MP3 player. The eGo's file transfer application could be programmed to pull down specific feeds to a user's PC every evening.

There were dozens of focused daily feeds covering national news, business news, entertainment news, even a recap of the previous days TV shows. The service lasted over a year, but succumbed when the I2Go company ran out of capital during the dotcom crash and folded. Archive.org has an August 2000 [http://web.archive.org/web/20000817184140/www.myaudio2go.com/asp/pgobject.asp snapshot] of the MyAudio2Go site.

In 2001, [http://www.applian.com Applian Technologies] of San Francisco, CA introduced [http://www.replay-radio.com Replay Radio], a TiVo-like recorder for Internet Radio Shows.  Besides scheduling and recording audio, one of the features was a Direct Download link, which would scan a radio publishers site for new files and copy them directly to a PC's hard disk. The first radio show to publish in this format was Web Talk Guys, produced by Rob and Dana Greenlee.

===Popularization===
The word about podcasting rapidly spread through the already-popular weblogs of Curry, Winer and other early podcasters and podcast-listeners. Fellow blogger and technology columnist Doc Searls began keeping track of how many "hits" Google found for the word "podcasts" on [[September 28]] [[2004]]. On that day, the result was 24 hits<ref>Searls, Doc. [[2004-09-28]]. Doc Searls' IT Garage, "[http://www.itgarage.com/node/462 DIY Radio with PODcasting.]"</ref>. There were 526 hits on [[September 30]], then 2,750 three days later. The number doubled every few days, passing 100,000 by [[October 18]].  A year later, Google found more than 100,000,000 hits on the word "podcasts."

On [[October 11]] [[2004]] the first phonetic search engine for podcasting was launched called [[Podkey]] to assist podcasters to easily connect to each other. Capturing the early distribution and variety of podcasts was more difficult than counting Google hits, but before the end of October, The New York Times had reported podcasts across the United States and in Canada, Australia and Sweden, mentioning podcast topics from technology to veganism to movie reviews<ref>[[Cyrus Farivar|Farivar, Cyrus]]. [[2004-10-28]]. "[http://tech2.nytimes.com/mem/technology/techreview.html?res=990CE3D6153DF93BA15753C1A9629C8B63 New Food for IPods: Audio by Subscription.]" in ''[[The New York Times]]''</ref>.  [[USA Today]]  told its readers about the "free amateur chatfests" the following February <ref>Acohido, Byron. [[2005-02-09]]. "[http://www.usatoday.com/money/media/2005-02-09-podcasting-usat-money-cover_x.htm Radio to the MP3 degree: Podcasting.]" in ''[[USA Today]]''</ref><ref>Della Cava, Marco R. [[2005-02-09]]. "[http://www.usatoday.com/money/media/2005-02-08-podcasting_x.htm Podcasting: It's all over the dial.]" in ''USA Today''</ref>,  profiling several podcasters, giving instructions for sending and receiving podcasts, and including a "Top Ten" list from one of the many podcast directories that had sprung up. The newspaper quoted one directory as listing 3,300 podcast programs in February, 2005. 

Those Top Ten programs gave further indication of podcast topics: four were about technology (including Curry's ''[[Daily Source Code]]'', which also included music and personal chat), three were about music, one about movies, one about politics, and&mdash;at the time number 1 on the list&mdash;''[[The Dawn and Drew Show]]'', described as "married-couple banter," a program format that USA Today noted was popular on American broadcast radio in the 1940s.  After Dawn and Drew, such "couplecasts" became quite popular among independent podcasts (those not derived from a preexisting radio show).

In March of 2005, [[John Edwards]] became the first national-level US politician to hold his own podcast<ref>[[John_Edwards|Edwards, John]], [[2005-05-22]]. [http://ga3.org/podcast/podcasting101.html One America Podcast]</ref>.  (He may be the first major politician to have a podcast; given the nature of podcasting, we may never know.)  Within a few episodes, the show had all the features of a major podcast: a web site with subscription feeds and show notes, guest appearances, questions from the audience, reviews and discussion of other media (in this case books), musical interludes of podsafe (noninfringing) songs, light banter (sports and recreation talk), even limited [[Soundseeing_tour|soundseeing]] from on location.  Later in the summer of 2005, U.S. President [[George W. Bush]] became a podcaster of sorts, when the White House website added an RSS 2.0 feed to the previously downloadable files of the president's weekly radio addresses<ref>[[White_House|White House]], [[2005]]. [http://www.whitehouse.gov/news/radio/ White House Radio Addresses].</ref>.

By mid-2005, the medium had acquired a bittersweet form of validation: a backlash.  Some experienced Internet users declared podcasting to be either nothing special (just a variant of blogs and mp3s), or already past its peak (because of growing exposure, and/or adoption by unsavvy Internet users).
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In June, 2005, [[Apple_computer|Apple]] staked its claim on the medium by adding podcasting to its free [[iTunes]] 4.9 music software and building a directory of podcasts at its [[iTunes Music Store]]. The new iTunes could subscribe to, download and organize podcasts, which made a separate aggregator application unnecessary for many users. From the beginning, many aggregators already had relied on iTunes to transfer the audio to the iPods that gave the form its name. At the iTunes Music Store, podcasters' directory listings were free, as were the podcast subscriptions -- but the service brought users to the iTunes Music Store to be exposed to its retail offerings. Apple also promoted creation of podcasts using its GarageBand and Quicktime Pro software and the MPEG 4, m4a audio format instead of mp3.

As is often the case with new technologies, pornography has become a part of the scene - producing what is sometimes called podnography. Other approaches include enlisting a class full of MBA students to research podcasting and compare possible business models<ref>Crofts, Sheri, et al. [http://firstmonday.org/issues/issue10_9/crofts/ Podcasting: A new technology in search of viable business models]. ''[[First Monday (journal)|First Monday]]'', September 2005.</ref>, and venture capital flowing to influential content providers.

The growing popularity of podcasting introduced a demand for music available for use on the shows without significant cost or licensing difficulty.  Out of this demand, a growing number of tracks, by independent as well as signed acts, are now being designated "[[podsafe]]".  (See also [[#Podcasting_and_Music_Royalties|Podcasting and Music Royalties]].)

In September 2005, the first podcast encoded in 5.1-channel encoded [[Dolby|Dolby Headphone]], was created by [[Revision3 Studios]] with their 14th episode of [[Diggnation]]. The Dolby encoding lasted for only a few minutes of the podcast.  On October 12, 2005 Apple Computer CEO [[Steve Jobs]] unveiled the first iPod with video capabilty. In his keynote speech he demonstrated the video podcasts [[Tiki Bar TV]] and [[Rocketboom]].  On December 03, 2005 [[Sony Computer Entertainment America]] announced that the [[PlayStation Portable]] would support podcasting using the RSS Channel feature after upgrading to 2.60.

"Podcast" was named the word of the year in 2005 by the New Oxford American Dictionary and would be in the dictionary in 2006.  
The term "podmercial" was coined in early 2005 by John Iaisuilo, a radio broadcaster/podcaster based in Las Vegas, who promptly trademarked it.  The term "poditorial" was coined by author John Hedtke in July 2005 while writing half of "Podcasting Now: Audio Your Way!" (The latter term is not yet trademarked.)  
<!-- cf. "Podcasting Now: Audio Your Way!", November 2005, for the etymology of "podcasting" and "podmercial"
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=== Adoption by traditional broadcasters ===
{{main|Podcasting by traditional broadcasters}}
Traditional broadcasters were extremely quick to pick up on the podcasting format, especially those whose news or talk formats spared them the complications of music licensing. While there had been experimental feeds of radio broadcast material, such as Dave Slusher's August 2004 feed of WREK programs from [[Georgia Tech]]<ref>Dave Slusher, 2004. [http://www.evilgeniuschronicles.org/wordpress/2004/08/27/experimental-wrek-rss-feeds/ Experimental WREK RSS Feeds].</ref>, the [[United States|American]] syndicated radio show ''Web Talk Radio''<ref>''Web Talk Radio'', [[2004-09-15]]. "[http://www.webtalkradio.com/blog/9.shtml WebTalk Launches New Website]."</ref> apparently became the first to adopt the format on a regular basis, in [[September 2004]], followed within weeks by [[Seattle, Washington|Seattle]] news radio station [[KOMO (AM)|KOMO]] and by individual programs from [[KFI]] [[Los Angeles]] and [[Boston]]'s [[WGBH]]. 

The [[BBC]] began a trial in [[October 2004]] with [[BBC Radio Five Live]]'s ''[[Fighting Talk]]''. These trials were extended in [[January 2005]] to [[BBC Radio 4]]'s ''[[In Our Time]]''<ref>BBC Press Office, 2005. "[http://www.bbc.co.uk/pressoffice/pressreleases/stories/2005/01_january/30/radio.shtml BBC podcasting sparks Fighting Talk]."</ref>.  Also in January 2005, [[Canadian Broadcasting Corporation|CBC Radio]] began a trial with its weekly national science and technology show ''[[Quirks and Quarks]]''<ref>Newitz, Annalee. 2005. "[http://www.wired.com/wired/archive/13.03/curry.html Adam Curry Wants to Make You an iPod Radio Star ]." In ''Wired Magazine''. See also: [http://www.cbc.ca/podcasting/ CBC Podcasting page].</ref>, which has offered listeners [[Real Audio]], [[MP3]] and [[OGG]] downloads since [[February 1996]]. The CBC trial also included [[CBC Radio Three | CBC Radio 3]]'s ''Canadian Music Podcast'' as well as limited podcasting of [[CBLA]]'s popular ''[[Metro Morning]]'' [[Toronto]] show. United States [[National Public Radio]] member stations [[WNYC]] and [[KCRW]] adopted the format for many of their productions. March saw [[Virgin Radio]] become the first UK radio station to produce a daily podcast of its popular breakfast show. In [[April 2005]] the BBC announced it was extending the trial to twenty more programs, including music radio<ref>BBC Press Office, 2005. "[http://www.bbc.co.uk/pressoffice/pressreleases/stories/2005/04_april/14/pod.shtml BBC to podcast up to 20 more programmes including Today and Radio 1 speech highlights]."</ref> and in the same month [[Australia]]'s [[Australian Broadcasting Corporation|ABC]] launched a podcasting trial across several of its national stations<ref>[http://www.abc.net.au/rn/podcast/help.htm#9 ABC Radio National podcasts].</ref>. In May, Sydney station [[2MBS]] became the first Australian community radio station to deliver content via the format, when its ''Ultima Thule'' [[ambient music]] programme was made available as a podcast.  

In late March, 2005, the trend began to go the other way, with podcasts becoming a source of content for broadcast radio programs by [[Leo Laporte]], [[Christopher Lydon]] and others.  On March 30 Sirius Satellite began playing Wichita Rutherford's podcast [http://www.5minuteswithwichita.com/ 5 Minutes with Wichita] making him the first person who started out as a podcaster to find a home on Satellite Radio.  The entire format of [[KYOU]] Radio, a [[San Francisco]] radio station, became based around broadcasting Podcasts.   That summer, when the [[Canadian Broadcasting Corporation]] locked out more than 5,000 of its regular on-air and technical staff, they responded by creating their own unofficial podcast of original programming, [http://www.cbcunplugged.com CBC Unplugged], which also appeared on some campus and community radio stations, including [[CIUT]] in Toronto and CFRU in Guelph, Ontario.

The most recent development has seen London's [[LBC]] 97.3 launch the world's first [http://podcast-audio.chrysalis.com paid-for podcasting service] [http://milk.shake.org/~coffeelover/archives/2006/01/paid_podcasting.html]. Subscribers get access to extra podcast channels and the use of an online podcast player similar to the BBC's Listen Again service. The technology used by LBC marks a watershed in podcasting, which until recently has been almost an entirely free phenomenon. Other broadcasters, anxious to generate some revenue to cover the costs of podcasting are almost certain to follow in [[LBC]]'s footsteps.

=== Coping with growth === 
While podcasting's innovators took advantage of the sound-file synchronization feature of [[Apple Computer]]'s iPod and [[iTunes]] software -- and included "pod" in the name -- the technology was always compatible with other players and programs. Apple was not actively involved until mid-2005, when it joined the market on three fronts: as a source of "podcatcher" software, as publisher of a podcast directory, and as provider of tutorials on how to create podcasts with Apple products GarageBand and Quicktime Pro. 

[[Image:itunespodcast.png|thumb|250px|right|Podcasts in the iTunes Music Store]]
When it added a podcast-subscription feature to its [[June 28]], [[2005]], release of iTunes 4.9<ref>[http://www.apple.com/itunes/ Apple &ndash; iTunes]</ref>, Apple also launched a directory of podcasts at the iTunes Music Store, starting with 3,000 entries. Apple's software enabled [[MPEG-4 Part 3#.m4a|AAC]] encoded podcasts to use chapters, bookmarks, external links, and synchronized images displayed on iPod screens or in the iTunes artwork viewer. Two days after release of the program, Apple reported one million podcast subscriptions.<ref>[http://www.apple.com/pr/library/2005/jun/30podcast.html iTunes Podcast Subscriptions Top One Million]</ref>

Some podcasters found that exposure to iTunes' huge number of downloaders threatened to make great demands on their bandwidth and related expenses. Possible solutions were proposed, including the addition of a content delivery system, such as [http://www.libsyn.com liberated syndication]; [http://www.podcastservers.com Podcast Servers];[[Akamai Technologies|Akamai]]; a [[peer-to-peer]] solution, [[BitTorrent]]; or use of free hosting services, such as those offered by [[Ourmedia]], [[BlipMedia]] and the [[Internet Archive]].

As of September 2005, a number of services began featuring video-based podcasting including Apple via its iTunes Music Store and [[Loomia]]. Known by some as a [[vodcast]], the services handle both audio and video feeds. As well as public broadcasting made possible by [http://participatoryculture.org Participatory Culture Foundation].

After the release of Apple's 5th Generation iPod in October 2005, which incorporated playing video files, Video Podcasting has became a major selling point for Apple. Apple's front page advertises the new iPod's Music, Photos, Audiobooks, Podcasts and Video Podcasting capabilities.

== Other uses ==	 
Podcasting's initial appeal was to allow individuals to distribute their own "radio shows," but the system is increasingly used for other reasons, including:	 
*A way for people and organizations to avoid regulatory bodies, like the British [[Ofcom]], that would not allow a program to be broadcast in traditional media. 
*A way for news organizations to distribute audio as an addition to their existing text (or mostly text) news products. For example, [[Wikinews]] began to podcast its News Briefs in 2005.
*Education.  In 2004 [[Musselburgh]] Grammar School pioneered podcast lessons with foreign language audio revision and homework <ref>[http://mgsonline.blogs.com/mgspodcast Musselburgh Grammar School Podcast]</ref>, other pioneers including [http://bobsprankle.com/ The Room 208 Podcast], [http://www.mpsomaha.org/willow/radio/ Radio WillowWeb], and [http://room613talk05.edublogs.org/tag/podcasts/ Room 613 Talk].  The online encyclopedia [[Wikipedia]] [[:Category:Spoken articles|podcasts encyclopedia articles]]. Dave Jobbings has an overview of educational podcasting<ref>Dave Jobbings, 2005. "[http://www.recap.ltd.uk/articles/podguide.html Exploiting the educational potential of podcasting]."</ref>  [http://epnweb.org/ The Education Podcast Network] lists a  range of podcast format teaching aids and support and a [http://www.recap.ltd.uk/podcasting/index.php Podcast directory for educators] lists podcasts produced by or for schools. 
*Politics.  In the U.S., both major political parties have various podcasts, as do several politicians.
*Religion. '''Godcasting''' has been used by many religious groups <ref>Heinen, Tom. 2005. "[http://www.jsonline.com/news/metro/jun05/333091.asp Podcasting becomes another pulpit]." In ''JS Online'', [[2005-06-11]].</ref>. Many churches produce podcasts of talks and sermons.  ''Disciples with Microphones'' provides podcasts relating to the [[Catholic]] church<ref>''[http://www.discipleswithmicrophones.org Disciples with Microphones]''</ref>.
*Unofficial audio tours of museums ([[musecast]])<ref>Kennedy, Randy. 2005. "[http://www.nytimes.com/2005/05/28/arts/design/28podc.html?ex=1274932800&en=db1ced6873dcc4b6&ei=5090&partner=rssuserland&emc=rss With Irreverence and an iPod, Recreating the Museum Tour]." In ''[[The New York Times]]'', [[2005-05-28]].</ref>.
*Official Cultural Historic Audio Tour of cities ([audisseyguides]).
*Communication from space.  On [[7 August]] [[2005]]. American astronaut [[Stephen Robinson| Steve Robinson]] claimed the first podcast from space  during the  [[Space Shuttle program| Space Shuttle]] [[Space Shuttle Discovery| ''Discovery'']] mission [[STS-114]] - although there was no subscription feed, merely an audio file that required manual downloading. ([http://www1.nasa.gov/returntoflight/crew/robinson_podcast.html transcript & audio]).
*Television Commentary. ''[[Battlestar Galactica]]'' writer and executive producer [[Ronald D. Moore]] creates commentary podcasts for each new episode of ''Battlestar Galactica'' ([http://www.scifi.com/battlestar/downloads/podcast/ download audio commentary]).  Other television shows have since followed suit.
*Conference and meeting alerts. Podcasts can be packaged to alert attendees to agendas, hosted roundtables and daily feedback.
*Advocacy. The 5,500 [[Lockout (industry)|locked out]] staff (editors, journalists, technicians, hosts, etc.) of the [[Canadian Broadcasting Corporation]] were podcasting news and other programming during August and September of 2005.
*Youth Media. Podcasting has become a way for youth media organizations, such as Youth Radio ([http://www.youthradio.org Youth Radio site]), to bring youth perspectives to a wider audience.
*Newspapers. Newspapers use podcasts to brodcast audio content from print interviews and drive traffic to their websites. The San Franciso Chronicle is believed to be the first major daily newspaper to start podcasting using an external website<ref>[http://sfchroniclebiz.blogspot.com San Francisco Chronicle Podcast].</ref> in Feb 2005. [[Hong Kong]]'s [[South China Morning Post]] was the first to use its own website and the first in Asia, having launched on April 19, 2005<ref>[http://podcasting.scmp.com South China Morning Post Podcast].</ref>
*Academic Journal digests: The Society of Critical Care Medicine has a podcast used to update clinicians with summaries of important articles, as well as interviews<ref>[http://www.sccm.org/podcast Society of Critical Care Medicine Podcasts]</ref>.
*In the second half of 2005, a Communication Studies course at the University of Western Australia ([http://i-generation.blogspot.com/ iGeneration: Digital Communication and Participatory Culture]) used ''student-created podcasts'' as the main assessment item.
* Public libraries can podcast local publications free of Copyright, offering spoken word alternatives to the visually impaired.

== Podcasting and Music Royalties ==
From the beginning, the use of licensed music in podcasts has been a delicate legal issue.  

=== Regular radio-based podcasts ===
Regular radio broadcasters' podcasts (and MP3 file downloads without subscription feeds) have run into complications regarding royalties for incidental music on "talk" broadcasts, even when identical programs are "streamed." The broadcasters apparently believe companies that license the music will challenge its use in easily downloaded MP3 files, while "streaming" is closer to a broadcasting model.

For example, when popular U.S. conservative commentator [[Rush Limbaugh]] began offering "podcasts" early in [[2005]], his employer, [[Premiere Radio Networks]], tightened its editing of intro and [[bumper music]], which it previously had allowed on other MP3 files. One effect was to render some of Premiere broadcaster [[Glenn Beck]]'s podcasts difficult to follow. He would appear to stop mid-sentence and restart in a different thought, because of cuts required to remove royalty-protected music.

The technology used by London's [[LBC]] 97.3 for its premium rate podcasting service may be applied in the future to podcasts which contain royalty-sensitive content such as music. As each user must pay a fee to access the audio, this may allow royalties to be distributed to the correct recipients. The nature of the statisics avaliable for each download may allow royalty distribution to be even more precice than the current system used by, say, conventional FM music radio. This may lead to an increase in music-based podcasts.

=== Future Licensing Issues ===
The [[US Congress]] is studying possible reforms to the [[Telecommunications Act of 1996]], which may in the future affect broadband and Internet services.

== See also ==
*[[Autocast|Autocasting]] (the automatic generation of podcasts from text-only sources)
*[[Learncasting]] (delivering instructional content or academic support)
*'''[[List of podcast directories]]'''
*[[Media RSS]] (a kind of syndication of media files used by [[Yahoo!]])
*[[MMS Podcast]] (podcasting to mobile phones using MMS)  
*[[Mobilecast]] (podcasting to mobile phones)
*[[Narrowcasting]] (podcasting is a form of narrowcasting)
*[[Palmcasting]] (podcasting to [[Palm]] devices like [[Treo]] and [[LifeDrive]])
*[[Photofeed]] (image podcasting)
*[[Punchcasting]] (punching podcasts directly into [[smartphone]] devices)
*[[Soundseeing tour]] (podcast utilizing ambient noise and descriptions)
*[[Streaming Media]]
*[[Vodcast|Vodcasting/Vidcasting]] (video-based podcasts)
*[[n:Wikinews:Audio Wikinews|Audio Wikinews]] ([[Wikinews]] audio project)

==External links==
{{wikibooks|Podcasting}}
<!-- 
Please do not add links to individual podcasts, podcast software, podcast cons or podcast directories (including Podcast Alley). Links should only be here if they help explain *what* podcasting is.  External links should explain Podcasting in more depth or from a different angle than Wikipedia can, they should not simply be a repeat of this article. 
-->

* [http://podcastforums.org The Podcast Forum]
* [http://www.podcast411.com/page2.html Podcast 411] A list of podcast directories and search engines. <!-- The reason why we have this link here is because this link leads directly to a list of podcast search engines.  We will gladly link to other lists of podcast search engines.  Links to individual podcast search engines will be removed.  See the "discussion" page for rationale and talk with us if you disagree. (User:Samboy)-->
* [http://www.podcast411.com/page5.html List of Podcasting Tutorials]
* [http://www.MyPods.Net/ MyPods.Net Podcasting explained]
* [http://blogs.wwwcoder.com/jrda/articles/podcasting.aspx Whitespace Blog "What's Podcasting?" article] 
* [http://www.digitalpodcast.com/PVCR_3Q_Update.pdf PDF Report examining podcast content mix]
* [http://peterchen.members.grokthis.net/research Report examining podcast producers and shows]
* [http://del.icio.us/tag/podcasting deli.icio.us podcasting tagged sites]
* [http://www.musicpodcasting.org AMP - Association of Music Podcasting]
* [http://www.podcasterswiki.com Podcasters Wiki]
* [http://www.shownotes.info/wiki/DSC_290#Adam.27s_History_of_Podcasting Adam Curry's version] of the development of podcasting at his shownotes wiki
* [http://archives.cnn.com/1999/TECH/computing/12/10/mp3.radio/ 1999 CNN report on MP3.com Stations] Pre-Podcast internet radio stations with a playlist concept.
===Open Source Podcast Receivers===
<!-- Open source.  If the source to the player is not public, don't list it here.  (User:Samboy) -->
*[http://amarok.kde.org/ amaroK] [[GPL]] is able to play podcasts (KDE/QT)
*[http://linc.homeunix.org:8080/scripts/bashpodder/ bashpodder] [[GPL]] a minimalist 45-line bash script receiver. A simple GUI is also available.
*[http://www.castpodder.net/ CastPodder] (formerly known as iPodder Linux version) [[GPL]] free Podcast receiver for Linux.
*[http://inforss.mozdev.org/ Inforss] cross platform extension for Firefox/Mozilla/Thunderbird that can detect podcasts within RSS feeds and play/download them while browsing. 
*[http://juicereceiver.sourceforge.net/ Juice] [[GPL]] Juice is a free, multi language, multi media-player, blind and visually impaired accessible Open Source Podcast Receiver implemented in Python. (Source available via cvs or in tarball [http://www.samiam.org/juice-20060114.tar.lzma here])
*[http://www.peapodpy.org/ Peapod] [[GPL]] command line podcast receiver for linux. Supports HTTP and BitTorrent.
*[http://podget.sourceforge.net/ Podget] [[GPL]] is a podcast aggregator optimized to be run from a cron job.  It's a simple command-line client with automatic playlist creation, support for FTP/HTTP/Torrent downloads, and importing servers from OPML lists.
*[http://prodder.sf.net/ Prodder] [[GPL]] a simple command-line Podcast client for UNIX-like systems.
*[http://www.podzy.com/ Podzy] is an AJAX podcast discovery tool/player
*[http://rhythmbox.sourceforge.net/ Rhythmbox] [[GPL]] is an integrated music management application (Gnome/GTK)
*[http://www.podsage.com/ Podsage] is a free podcast and vidcast aggregator and player for windows.  It has an inbuilt library of links to over 27,000 podcasts; 240,000 episodes, and 100 OPML sites.

[[Category:Podcasts]]

Wiki Source: [http://en.wikipedia.org/wiki/ Wikipedia]