> I think what's much more likely is that machine learning algorithms are so good right now, they're able to determine what people are interesting in based on b

> I think what's much more likely is that machine learning algorithms are so good right now, they're able to determine what people are interesting in based on browsing habits and other metadata. I and a friend were discussing this before that podcast. He was of the opinion that FB was very likely listening because he had multiple occurrences where he'd visit family, and they'd talk about something, either some product that family was interested in or had just bought, and hours to a couple days later he'd see an advertisement for it. My stance (which looks to be the same as yours) was that they don't even need to listen to you, and doing so would probably be really bad if it was found out. Instead they know who you're around, they what that they're interested in, and they make some educated guesses and tag you as interested in stuff they are also or that they just bought, and it's the hits that stick in our mind, not the random other stuff you were shown that you never talked about with others but they had searched for or bought. Throw enough data at he problem, you'll get some hits. There's a lot of data out there right now.