So. . . what IS a Podcast?
Usually a podcast features one type of 'show', with new episodes released either sporadically or at planned intervals such as daily or weekly. In addition, there are podcast networks that feature multiple shows on the same feed.
Podcasting's essence is about creating content (audio or video) for an audience that wants to listen or watch when they want, where they want, and how they want.
(definition taken from Wikipedia)