Podcast and marketing

Hello team! I am thinking of ways to build value and aside from blogging the other idea I had was to start a podcast. I’ve podcasted before for my previous corporate job so I know the ins and outs but my question is more geared towars marketing. Did Jody and other coaches advertise their podcast to get the word out or was it all organic? My list is new as I am starting a new niche. I ask this because a few months ago I had dabbled with posting audio on YouTube and got zero views. This was just an experiment but looking back now, as I seriously consider launching a podcast I am wondering if advertising is a must. Thank you.