Podcasting, blogging, video blogging, etc. are for the majority about expression; not about monetizing and building reputation (although I luv those folks too!).
While blogging can be about playing on a world stage to influence, gain audience, and, potentially, monetize (the same goals as most other media), there are millions of people who are happily pubishing daily without those motivations. For them, it's more about expression, self-reflection, and communication.