When listeners subscribe to your podcast in their apps, they are really subscribing to a RSS URL. RSS feeds are used to send regularly updated or changing content to other web services.
We recommend having two RSS URLs associated with your podcast: a public feed and a private feed. This allows you to have freedom over URL branding and any future distribution changes you make. Typically a podcast RSS URL is specific to the hosting service, which means if you ever want to leave your hosting service you will need to create a new feed and initiate a redirect. If you already have a feed proxy in place then all you have to do to move hosts is update the source feed.
For example, a feed created through PRX looks something like: https://f.prxu.org/xxx/feed-rss.xml. You can see that it is specific to PRX. This is what you would use as your private feed, not to be shared with listeners. Instead, you would create a public feed, which is a proxy or a mask for your private feed. It might look something like this: http://feeds.feedburner.com/mypodcastnamehere.
If listeners subscribe to the public feed, you can change podcast host sites without ever disrupting your public URL and potentially losing subscribers.