xml - What is this special feed format?

Question

I noticed some podcasts in iTunes have a different sort of feed. For example:

https://itunes.apple.com/us/course/exploring-the-hobbit/id598674517

has a feed that includes <itms:storelink> tags on some items, urls on other items:

https://itunesu.itunes.apple.com/WebObjects/LZDirectory.woa/ra/directory/courses/598674517/feed

What are these for, is this a sort of new url-shortening Apple invented?

Here is another podcast:

https://itunes.apple.com/WebObjects/DZR.woa/wa/viewPodcast?cc=us&mt=10&id=524106825

which links to a standard rss:

https://deimos.apple.com/WebObjects/Core.woa/Feed/umich-public-dz.15286326948.015286326950

So why are there two different formats on the same iTunesU service? Is this new format of feed with <itms:storelink> documented anywhere?

Answer 1

itms links open in the iTunes store directly. After reviewing the first feed, I'd suggest that the items including the itms:storelink tag are hosted by iTunes, as there are items that use the enclosure tag instead, which are probably hosted on some other server.

The two feeds are different because one is ATOM and the other is RSS.

See: How to link to apps on the app store