I am new to Joomla so I want to know if it is possible to build a podcasting site with user registration on Joomla.
I want guests to be able to subscribe to an individual user's podcast (not subscribing to the whole blog).
Is it possible to do this using Joomla?
A podcast is just another form of content in a file therefore yes you can and the second part of your idea is going to need some form or subscription/payment process.
A quick Google and this article by Peter B. describes the general steps for setting up the podcasting environment, https://joomlabe.at/joomla-advice/management/how-to-podcast-with-joomla The article is a little bit old so some of the extensions mentioned may no longer exist but you should get an idea of what is involved.
I would suggest you look at the various Subscription extensions available in the Joomla Extension Directory(JED, https://extensions.joomla.org/) in particular ones that handle files for downloading and may integrate with some of the podcasting extensions in @AHeavyObjects answer.
You could also look at sites like OST Training/Joomlashack that provide the extensions they use to manage their online learning and recurring subscriptions to see if their model might be helpful in what you want to do.
Pure Joomla doesn't allow this. You may try to find an extension https://extensions.joomla.org/instant-search/?jed_live%5Bquery%5D=podcast
But there is a great chance there is no extension doing exactly what you want. So workarounds or customization will be needed.
On the other hand, Joomla allows to develop an extension to do what you need.
