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Podcasting 101

Podcasts are popular. In fact, they're all the rage, something you're likely to hear about at the watercooler, on the news, or from your teen-age son or daughter.

Podcasts are popular.
In fact, they're all the rage, something you're likely to hear about at the watercooler, on the news, or from your teen-age son or daughter. They're so big that last year the New Oxford Amer-ican dictionary named "podcasting" its word of the year. (It beat out "bird flu" and "sudoku" for that honor, which is no small feat.)

It's an honor that's well deserved. Google turns up hundreds of millions of hits for the terms 'pocast' and 'podcasting.' That's a lot of buzz for a new way to download audio and video over the Web.

So what's all the buzz about? In part it's about choice, that elusive concept that technology—and the Internet above all—are supposed to give us. People can listen to podcasts about Puccini, pasta, soccer, or Muggles (the Harry Potter word for those luckless humans who can't work magic). A quick trip to Podcast Alley (www.podcastalley.com, a major podcast portal) turns up podcast titles like "Zaldor's World" (a podcast about a father who likes to sing in karaoke bars) and "JivaDiva Yoga Jam"(about—you guessed it—yoga).

But podcasting is also about control. You can listen to podcasts when and where you like, with nearly any computer or Ṃ player in existence. That means you can listen in the privacy of your own home, at work (some companies even use podcasts instead of newsletters or email or use them for corporate training), or on the subway, using your favorite Ṃ player.

So what is a podcast? It's a recording(most often audio, but sometimes video) that you can download on the Web, using special software to let you know that a new podcast has been published. The software is called a podcatcher or aggregator and relies on a simple technology called feeds, which in turn are powered by systems called RSS and ATOM, which we'll explain below.

Podcasts come in dozens of formats, from simple, off-the-cuff recordings made in people's basements to slick corporate affairs to hawk new products. They can sound like talk shows, monologues, or even well-rehearsed plays and can give you information that often can't be found elsewhere.

Born From Blogs

First, let's take a look at the word itself: "podcast" is a blending of "iPod," the world's most well-known MP3 player, and "broadcast." (If you don't have an iPod, don't worry: You don't need one to make or listen to podcasts. Any computer with speakers or any MP3 player will do.)

Adam Curry, one of the first MTV VJs, is often named as the father of podcasting, but in truth he's only one of the people, including a number of wellknown bloggers and programmers, who made podcasts possible. In late 2003, when blogging was all the rage, intrepid souls began to experiment with voice blogs, a way to package recordings and distribute them with the same RSS tools that blogs used. (RSS, which stands for RDF Site Summary, Rich Site Summary, or Really Simple Syndication, depending on who you ask, is a way for Web site owners to let readers subscribe to a Web site's content—but more on that later.)

Using the human voice appealed to early bloggers, as bloggers of all stripes like to hear themselves talk. And it opened up new techniques for blogging, including the interview. In fact, the first podcast is thought to be Christopher Lydon's, a former New York Times reporter and NPR host, who recorded interviews with 25 bloggers and politicians and released them on his blog while he was a fellow at Harvard Law School. The first person to coin the term "podcast" was a reporter, Ben Hammsersley of The Guardian. In 2004, he noted that blogs using the human voice and not merely text could lead to a surge in amateur radio and wrote, "But what to call it? Audioblogging? Podcasting? GuerillaMedia?"

The trend caught on. Within months, bloggers around the world were recording their rants, raves, and even their recipes with simple microphones and PCs and then posting those recordings to their Web sites and making new connections across that most impersonal of networks, the Internet.

And they weren't alone. Radio stations, newspapers, magazines, and large, well-financed Web sites started to podcast, sensing a new way to spread their message.

Beware Imposters

Today, podcasting is used as a catchall term for any kind of recording, audio or video, that you download over the Web. But that's misleading.

Podcasts are recordings that download to your computer, iPod, or other Ṃ player without lifting a finger, using an RSS or Atom feed. The key word here is "automatic." People who listen to podcasts use special software, known as podcatchers or aggregators, to subscribe to feeds that interest them. Some of the most common podcatchers are Juice (ipodder.sourceforge.net) and iTunes (www.itunes.com), the digital jukebox software that began on Macs. (Both Juice and iTunes can be used on Macs and PCs; Juice will soon be available for Linux machines as well.)

Podcatchers and aggregators often start up when you boot your computer. They check Web sites and podcast directories for new content (you can choose the interval at which they check, from a few minutes to a few mont

4s) and then download the new podcasts they find.

If you're not using a system that follows this model, you're not using a podcast. Podcast "imposters" include much if not most of the audio and video you find on news sites, such as CNN.com or ABCNews.com, or at special providers such as Real.com. Most of their recordings are streaming—that is, they start to play on your computer as soon as a portion of the document has been downloaded. And because they're streaming, they can't be stored, listened to later, or archived. You have to listen to them as soon as you start the download.

This model, in which you visit a Web site and point-and-click your way to its content, is known as the pull model of delivering content. It differs from the push model of podcasting, in which publishers (that is, bloggers, podcasters, and other Web site owners) send the content to you, most often because you've asked for it by subscribing to a feed.

An early example of the push model was PointCast, a wellpublicized Internet start-up that pushed news, weather, stock updates, and other content to users' desktops and screen savers using special software that users had to download and install. (Alas, PointCast went bust when Internet stocks lost their sheen, but podcasting is here to stay because it has devotees around the globe.)

Getting Technical:
RSS & Atom

The push model depends on feeds, which are simply the geek's term for a subscription, a way that your computer can check for new content and download it for you. (Feeds can include more than just podcasts: They can include news, graphics, songs, or any type of content the Web can accommodate.)

You may have seen a feed without knowing it, as most well-known Web sites and nearly all news sites use them to get their content out. For an RSS feed, just look at the bottom of a site for a small orange and white button with the letters XML or RSS. (XML, which stands for Extensible Markup Language, is the language that feeds are written in.) If you have a feed aggregator or podcatcher, all you have to do is click the icon and follow your software's instructions. Each program is different: Some will add the feed for you automatically, while others will prompt you to click a few buttons or copy and paste the feed's URL into the aggregator. But no matter what the process, it only takes a few seconds to subscribe to a new feed. The icon for an Atom feed is a larger blue button; again, just click it, and your software will prompt you to proceed.

RSS and Atom are the two most common feed technologies, though RSS is far more popular. In it, content authors write a brief document called a Webfeed, stream, or channel using XML Web code. The author then posts this document, which includes the location and description of the content he wants to publish, to his Web site and registers it with an RSS portal, such as www.Syndic8.com or www.RSSFeeds.com. Podcatchers monitor those directories—or simply the original Web sites themselves—to see when a feed has new content and then download the content to the end user's machine. Depending on the software you use, it may even transfer a podcast to your MP3 player for you, so you don't have to.

Atom, the second feed technology, works much the same way, but offers some technical benefits over RSS. For instance, it can include HTML within the XML language of the Webfeed. (HTML, or HyperText Markup Language, is the language used to write a Web page.) It also has a few other features that make it simpler to distinguish the content of a feed from an excerpt of that content and relies on XML standards in ways that RSS does not (a point that Web designers and other technical mavens especially like).

But to consumers and everyday technology buffs, RSS and ATOM are largely alike. If you're thinking of making your own podcast, the choice of RSS or Atom will most likely be made for you. Different Web sites, such as Blogger, TypePad, and Yahoo! GeoCities (which are popular blogging, podcasting, and Web hosting services), make their own choices about feed technology based on the needs of their designers and programmers.

Because most podcatchers and aggregators can use both RSS and Atom feeds, there's no reason to lose sleep over the difference—unless, of course, you're a techie at heart. Of far greater concern is which podcast you'll listen to, as there are millions—perhaps soon to be billions—in the podcasting universe. So open up your Web browser, get online, and start surfing. . . . Your first podcast is waiting for you.