Problem: You want to subscribe to a podcast, but you are unsure of which of the subscription icons you should choose. Here is a rundown of the typical icons used by most podcasters.

Podcast RSS
The RSS icon designates an XML feed intended for an RSS (Really Simple Syndication) feed aggregator. The RSS icon link enables quick feed subscription to an RSS feed reader, or, in the case of podcast feeds, provides a link that can be copied and pasted into a podcast receiver (or MP3 player application). This link uses the standard http protocol and is the safest option for all users because it allows the podcast to be used by most applications, including iTunes

Example: http://www.example.com/podcast.xml

One-click iTunes Subscription
This icon designates a one-click subscription to the podcast feed via iTunes. The one-click subscription is accomplished by using a different protocol, called itpc; otherwise, it is the same URL as the RSS link. Upon selection, the link automatically opens the iTunes application without requiring the user to take any other steps.

Example: itpc://www.example.com/podcast.xml

(Windows Users: You must have iTunes installed to use a one-click podcast feed. If you do not have iTunes installed, this feed will fail.)

iTunes Podcast Directory Entry
This link leads to the podcast's page within the iTunes Podcast Directory, where you can preview episodes and subscribe to the feed. The ability to preview episodes prior to subscribing is the main advantage of this option.

Example: http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewPodcast?id=FEEDID