Here's the fun part, they don't need to listen to you. You are far more predictable than you realize. They already know everything about you, what you search, what apps you use, what kinds of exercise you do and when, what you eat, what articles you read, movies and podcasts you consume, music you listen to, what you buy, where you go, who you hang out with, and everything about the people you hang out with. Every minute of your life is meticulously tracked and analyzed and compared to the hundred thousand people who are just like you in terms of interests and patterns. They can predict to a scary degree what your thinking before you might even realize it yourself. They know you better than you know yourself. Why waste the resources sifting through hours of recordings when they already know everything going on in your head from the million data points you voluntarily transmit to them everyday?

The other part of this to keep in mind is that you are bombarded with ads all day most of which you ignore. It's just that those few times where they manage to hit a straight bullseye, showing you an add for something you were just talking about or even just thinking about, those are the ones that will stick in your memory.