It could also be used to prevent showing an opt-in notification at all even in software that requires opt-in.
This flag is sent by my browser when I connect to SOMEONE ELSE’s SERVER.
The internet only took off because the primary business model which ran on ads and derivative information that servers do to their users.
It’s not fun. It’s not private or secure. It’s not illegal (in most jurisdictions for most industries). The flag exists as a response to the de facto and de jure state of the world, not some fairytale scenario.
No? It took off before advertising was widespread as a primary or sole funding business model? Also there's literally nothing about advertising that requires data collection about users. Sure they love to do it, and they might even believe that it helps their profits in some way. But it's not inherent, they got along just fine with billboards and newspaper classifieds. TV ads never required personal information. Not did pre roll cinema ads, or radio adverts. Nobody was bemoaning in the streets that they couldn't possibly find anything to buy
quite the opposite I would argue:
https://nickyreinert.de/2020/2020-10-24-marketing-killed-the...
No, it's set in your command shell (e.g. bash) and tells CLI programs that support it to not connect to a server. It has nothing to do with browsers or ads. This is all very clear in the article.
Get off your high horse.
Arguable, on the other hand it did kill the internet. (or, almost so far, we'll see whether we rebound after decades of enshittification)
...and promptly, thoroughly ignored.