Where podcasts have evolved I still think of them as audio content even though video podcasts seems to be growing.  Never thought of it as talkiing ebooks. Streaming content fits with the definition of what a podcast is which used to include access it via an RSS feed.  

To me, it's audio, but the 'cast' part implies a continuously (regularily or irrgularily) updated clip, about something that just happened around a topic (the reason for people to subscribe), plus an archive of old clips. 

Pod casting? Is that like throwing away the shells of the peas?