Audio has been around since, I suppose, the spoken language. The difference now is distribution and availability. Audiobooks, podcasts, smart phones, voice controlled home speaker systems, connected cars, and who knows what will come next.
This is where things can get exciting with your book as a podcast as opposed to (or in addition to) an audiobook.
I’m not sure I would have included Podcasts as a section in Audio for Authors had it not been so easy to create a...
I love listening to audiobooks - I always lose my glasses, but if I have an audiobook, I don't need them.? -- Michaela Coel?