Podcasting can be described in many ways.
From the perspective of the way it works, it is on-demand audio through the internet. It can be anything: someone’s opinion such as a lecture or an insight, a casual conversation, a radio show, a review of a book or movie or someone trying to be a DJ. There is lots of variety for any taste.
I think a more interesting perspective of podcasting is about what it makes possible. For me, it allows to find the time to listen to something interesting that engages my brain while doing some repetitive or boring task such as a chore, cleaning, cooking, shopping, of course lab work or even walking and taking photos. There is often plenty of brain power to engage with something else during such activities. And the ease by which it can be achieved is close to a sufficiently advanced technology to be indistinguishable from magic.