Following a creator means that you will see an item in your feed whenever that creator makes a guest appearance.

If you want to receive an email notification for this, click the “Following” green button on their creator profile. This will show the "Alerts" setting. Toggle this on to get notification of new credits. If a creator is a recurring podcast host, it will not appear in your feed every time they host their show, only if they make a guest appearance on another podcast.