A podcast is essentially an amateur audio file uploaded to the Internet and automatically distributed to subscribers.

Although some traditional media have created their own podcasts, the craze has grown largely on the popularity of the unpolished musings of hobbyists doing it for love or fun.

Because the phenomenon has grown alongside Apple's hot-selling iPod, it's taken the popular player's name and crossed it with broadcasting to get -- podcasting.

The word's association with Apple's popular portable player is misleading, however: users don't necessarily need any type of portable player, let alone an iPod, to listen in.

So, what is a podcast?

What weblogs are to print journalism, podcasting is to broadcasting, boosters say. They trumpet the ability of anyone with access to a suitable computer to produce what amounts to a syndicated radio show for next-to-nothing.

Unlike radio, the shows can be paused, rewound or even stopped and started again sometime later. And unlike streaming web radio, you can leave the Internet behind.

"You can listen to it off your desktop PC, but the big advantage is you can download it with your iPod and take it with you, listen to it any time," technology expert Kris Abel told CTV's Canada AM.

There are no set time limits, firm deadlines or censorship of what's included.

And when it comes to choices, the variety is vast. Virtually anything goes, as long as the creator is excited enough about the topic to actually make it.

From home brewed rants about pets or politics to slick corporate repackaging of previously broadcast content, it's all there.

One of the shuttle astronauts even did his own podcast while in orbit aboard Discovery.

How did it all begin?

Former MTV Veejay Adam Curry is credited with popularizing podcasting, after he recognized the potential of web technology called Really Simple Syndication, or RSS, to push podcasts onto users' computers and portable devices.

After convincing RSS co-inventor Dave Winer to update the text-based protocol to include audio file attachments, Curry came up with the program iPodder in late 2004, that automatically loads podcasts onto users' iPods.

From there, the Internet community seized on and improved his idea. At its essence a simple subscription concept, it's grown from there.

"Everytime there's a new episode, it will check for you, download it in the background, and the next time you check for your podcast, the latest episode is there waiting for you to go," Abel explained.

What are the signs podcasting 'has arrived'?

• The word 'podcast' has been included in the latest edition of the Oxford English Dictionary.
• Infinity Broadcasting announced plans to convert struggling San Francisco talk radio station KYCY-AM 1550, to an all-podcast format.
• Sirius Satellite Radio Inc. launched a show that features a daily selection of homemade podcasts, hosted by the former video jockey who claims to have initially popularized the whole idea, Adam Curry.
• Apple's latest-generation iTunes software, released in June, has built-in podcasting functions that make it simple to subscribe to and organize podcasts.
• U.S. President George Bush became a podcaster of sorts in July, when his weekly White House radio addresses were made available via RSS.

Far from a mature technology, however, podcasting continues to grow and evolve.

Sound-seeing, for example, involves the taking the recording studio on the road.

"Somebody takes off the big headset ... and instead uses their cellphone and the little hands-free to record a podcast to their cellphone," Abel explained. "There's a lot of advantages because then they can walk out and actually go to exotic places and give a description."

Because the podcasting concept can be applied as to video files as easily as it can to audio, trend watchers have an eye out for the emergence of home-grown TV.