In pre-Web times, marketers counted noses. With the advent of the Web, eyeballs. Ears are next.

Who will keep our ears well filled with portable entertainment while we move about?

On the one ear are older media repackaged and sold in digital form, like music and audio versions of books and magazines. On the other are podcasts, the audio programming from the masses that has popped up in the past year, available free.

“Podcast” is an ill-chosen portmanteau word that manages to be a double misnomer. A podcast does not originate from an iPod. And it is not a broadcast sent out at a particular time for all who happen to receive it.

It is nothing other than an audio or video file that can be created by anyone — add a microphone to your computer, and you’re well on your way.

The file begins its public life when you place it on a website, available for anyone to download to a computer and, from there, to transfer to a portable player, which may or may not be an iPod.

It’s encoded in such a way that the receiving computer can pick it up in successive installments automatically, whenever they are posted to the website. Subscribing is the term used for the automatic downloads, and it’s apt.

The delivery mechanism for a podcast subscription is rather slick. There’s no need to go to the trouble of browsing the website again for fresh material: The new stuff moves without so much as a beep from the original server to your computer. Then it moves automatically to your attached portable player, keeping the content perpetually refreshed.

Welcome to the post-Web era.

If new programs are added daily, you may begin to regard it as a new form of radio broadcast, ready whenever you happen to be free.

But the seemingly trivial technical fact that you cannot begin to listen to the program before the file transfer is complete turns out to have important legal implications.

A podcast falls in the not-a-broadcast category, which is otherwise known as file-sharing. It cannot include copyrighted music without authorization from the copyright owners. This is why podcasts are not the place for aspiring disc jockeys to realize their fantasies.

Preparing to receive podcasts for the first time used to be cumbersome. You had to install a layer of “podcatching” software on your personal computer, which constantly checked the sites you subscribed to, to see if new installments had been posted. The software also took care of the mechanics of the transfer to your computer.

Last month, however, that problem was removed in one brilliant, dazzling flash, when Apple released a new version of its iTunes software with podcatching capability built in.

Given Apple’s sleek online music store, it is no surprise that it has designed an elegantly simple way for visitors to subscribe to podcasts, too. What is unexpected is the variety of initial offerings.

Blogs rendered into audio form are a natural for podcasting, and their likely appeal to strangers can be expected to be about the same as that of the text versions — or even less, given the time-consuming nature of skimming audio.

But audio blogs constitute only one of the 21 subject categories offered at iTunes’ podcast directory. A smattering of recognizable brands — news programs from ABC News and ESPN and the British Broadcasting Corp., political commentary from Al Franken and hip tips from the Queer Eye for the Straight Guy Fab Five — help to pull the curious in.

Gene Munster, senior research analyst at Piper Jaffray, said the podcasting phenomenon had simply become too large for Apple to ignore — it had to embrace it or resist it. By opting to embrace, the company regains the revolutionary aura; by introducing many people to podcasts, he added, Apple “will reinvigorate conversation about the iPod.”

Apple’s decision to add free podcast subscriptions to its store shelves creates potential problems for another supplier: Audible, Apple’s exclusive supplier of more than 17,000 audio book titles for the iPod. At its own website, Audible sells the audio books, either a la carte or as part of a subscription bundle.

It also exclusively sells audio digest versions of well-known periodicals, including The Wall Street Journal, The New Yorker (a new offering) and The New York Times. Click to subscribe, pay and your portable player will be automatically updated, just like a podcast subscription.

The only difference is that intermediate step of “pay.” Will no-name podcasts dent Audible’s famous-names business?

It’s impossible to imagine Audible’s happy and healthy situation today without noting that it is the direct beneficiary of the wondrous success of the iPod.

More here.