> Ie, You can disable all 'related videos'/feeds/home page on Youtube with Unhook

This is not specific to YouTube. It’s billboards, product placement, etc etc etc.

> You can also easily never speak to them. I know they exist, but as a consumer I can't think of anytime I've had a sales interaction with a salesperson

Ok, so you make every major purchase online, probably don’t own a car, never purchased a home or lived in a city where its extremely difficult to rent without a realtor, never go out to restaurants or bars in the US where the service staff essentially works on commission in the form of gratuity… sure thing.

Thinking Sony would sell just as many products entirely based on word of mouth is absolutely absurd.

And as an aside, conversion measurement is der rigueur in digital advertising— for obvious reasons, companies don’t publish it. It is the basis for A/B testing which uses large sample sizes to see which presentation is more likely to make people do or not do something. It’s easier than ever to tell where someone was exposed to something and the click trail they took to end up on a purchase screen. I don’t, nor have I ever worked in digital marketing, but this information is extremely easy to find. Additionally, the Freakonomics guys are no strangers to vibing their way through topics they know nothing about and mistakenly assuming their brief thought experiments and unchallenged researchers have uncovered something useful. It’s not like they’re never right, but they’re no stranger to unforced errors in their analysis and you’d be wise to not rely on them as a source.

I somewhat suspect our difference here is cultural divide - I've never been to the US, but none of the things you mentioned have involved salespeople in my experience in Europe.

I live in a city, have a car (bought second hand), buy things in person, go to restaurants. We have no tipping or gratuity, apartments have a fairly standard application process and often it's a previous tenant showing you around because they want you to take over their lease, unless the apartment is empty.