data usage and podcasts

No, definitely not.

However, you should read on, as there is widespread confusion about the term Podcasts.

The term "a podcast" is actually rather confusing. An episode of audio programme (or even video) is downloaded "as a Podcast", it is not "a podcast" in its own right. In other words, one can usually listen to a radio programme either:

• • live - on a radio (as it is broadcast)
  • as a live stream - via the internet, as the episode is going out on the radio
  • a stream - on the internet, after the episode has been broadcast
  • by downloading it as a Podcast (via a Podcatcher), after it has been broadcast

And of course, many independent, non-radio programmes are available for download, as Podcasts (and in many cases, by streaming).

An iPod Touch can download a Podcast while on a Wi-Fi connection, for example, while you (and your iPod) are at home. That episode is then stored on the iPod, for listening even when not connected to the internet. When you listen to a downloaded episode in the car, your iPod is playing from that stored file on the iPod, so does not require any internet connection. While in your car, you will not be able download any episodes of any Podcasts, therefore, none of your data allowance on your home Wi-Fi is used.

But here's the confusion:

I have noticed in recent months that some people in the podcasting industry (who should know better) refer to "playing or listening to a podcast" when they are referring to "listening to a stream" of the episode. This is incorrect. Streaming, and Podcasting are different delivery methods (as is radio). Users can choose to have the programme delivered to them as a Stream or as a Podcast. A user can also choose to have a radio programme delivered as a radio programme.

• Listening to a programme as a stream means that the episode is being sent to your device in real time. What this means is that you cannot "stream" audio to an iPod Touch unless you are connected to a Wi-Fi signal
• One can listen to a programme as a stream on an iPhone, because the audio data is being downloaded (or sent to) the phone as you hear it, not via Wi-Fi, but by using the phone's data connection. In this situation, this will use some of the phone's data allowance
• Some very new cars have Wi-Fi connections. That Wi-Fi connection is possible because the car has a data connection to the internet, usually with a monthly data allowance. So in this situation, if one streams a programme to an iPod, via the car's Wi-Fi connection, then data usage is incurred. If you download the Podcast version of a programme, in your car, using the car's built-in Wi-Fi, this too will use up some of the car's data allowance

To summarise:

If you download programmes at home, as Podcasts (via your home Wi-Fi ) and then play those Podcasts in your car, no data usage is incurred while listening in the car.