Subscribing to a feed that contains podcasts is done the same way you'd subscribe to any feed. Go to the Feeds page, paste the address of the podcast feed into the text box at the top of the page and click the Submit button.
During a scan, when River2 detects a podcast, it adds it to a queue, and then in a separate thread, downloads podcasts in the order they came in, one at a time. You can see all the podcasts, in reverse-chronologic order, on the Podcasts page. Once a podcast has been downloaded, its icon changes from a music player to a folder. When you click on the folder, the Finder or Explorer comes to the front and the folder containing the podcast opens. You can then copy it to your music player or play it on your desktop or laptop computer. It's especially useful on netbooks.
Podcast feeds can be cloud-enabled, which would allow realtime distribution of audio and video programming. And podcasts can be part of reading lists.
The default folder is named Podcatcher and is on your desktop. You can change that on the Prefs page.
You an also set a maximum number of megabytes for the Podcatcher folder. When a download causes the folder to exceed the set limit, files are deleted, oldest-first. The default for this pref is 1000 megabytes.