Imagine if you could share the notes. And the notes could be structured. And you could tweak your player to react to notes in various ways. We could have crowd-sourced ad-'blocking' on podcasts!
Actually I have extensive time stamped notes for hundreds of podcast episodes including their ads starting and ending, but personally I'm against ad blocking. I've been in the process of removing those parts before publishing my bookmarks/notes.
I think I agree, much as I hate ads! There is something about podcast ads that I find much more acceptable than most other forms; the only slight downside is they tend to be quite repetitive, both within shows, and across them.
It would certainly be useful to have notes for a whole range of other benefits e.g. making it much easier to search an old episode for a specific topic.
That's actually why I started tracking the ad times. The same podcasts I listen to usually rotate through the same ads. So I would end up skipping them and noting it for fav episodes that I might come back to. Same issue ads on YouTube or Hulu when they become repetitive. I'm trying to not be against ad blocking, but when that happens, it's almost impossible to not be annoyed.
If you think about it as "bookmarking" - no, don't care. Bookmarking usually implies a manual, fragile process.
Being half way through on iOS, then being able to continue listening exactly at the same point on MacOS - yes. That's something iTunes and the iPod supported since day zero, and nobody else has yet properly replicated. And it's really useful if you listen to podcasts longer than about five minutes long.