2) in a vast global experiment where advertisers knew everything about everyone they still completely failed to show people relevant ads. Most notoriously even the giants who know what you ate yesterday fail to realize you probably don’t want ads for toilets for a year after you bought a toilet.

You want millions of people to loose their lively hood over this issue? That sounds cruel and spiteful to me.

You also have to think of many small companies that make niche products that would no longer be able to find their customers and thus be forced to close.

> 2) in a vast global experiment where advertisers knew everything about everyone they still completely failed to show people relevant ads.

The premise of your statement is false, advertisers have never know every thing about anyone. That was just marking bullshit by ad-tech companies targeted at adversities and publishers, "We know everything about your users! So if you hire Acme Ad Tech your profits will go through the roof!" The fact that users hear the statements and understandably freaked out was collateral damage. The fact this statement was demonstrably false was irrelevant.

The fact is that the amount of data used to do targeted advertising is quite sparse in-fact, no-one wants to spend the effort to individually go through mountains of data and figure out the best advertisment. Really the only data used is

1. demographics (age, gender) 2. location (this is so a NYC based restaurant chain doesn't waste money advertising in California), 3. language (people actually hate seeing ads in a foreign language) 4. interest categories (like do you like Football, or Cars, or video games, this is how facebook advertises a lot they figure out your interests based on posts, then allow advertisers to advertise to you based on that category, (interestingly they don't actually sell the list of interests mostly because that would mean advertisers would not have to buy ads through Facebook and more)) 5. product targeting (this is you visited acme.com and put an acme roadrunner trap in your cart but never checked out so now it follows you around the internet.)

> Most notoriously even the giants who know what you ate yesterday fail to realize you probably don’t want ads for toilets for a year after you bought a toilet.

Yeah, that's my point, using more data (like the fact you bought the toilet) is more work and using the current amount of data works well enough for them so that is all they do.

Training for teachers? Security services? Access control systems? Yes, a lot of those reading are parents, not teachers, but what do you think they'll do if they are convinced something exists that will reduce the risk of school shootings?

Editing: ad "targeting" as it has existed so far has also been insultingly, embarrassingly bad IMO. Even Google tried for years to send me ads for Russian, Ukrainian, Philippine and Thai dating sites. Round robin. I was delighted when they started showing me Wordpress ads.

Those are not relevant either but now we are approaching something useful and not actively insulting (I'm very happily married and have small kids.)

I suspect that most advertising is actually driven by supply (that is, somebody wants to advertise X), not demand (somebody needing Y at the moment), and that's why targeting doesn't really work that well, and the disadvantage of untargeted ads (or targeted by content) is much smaller than advertising industry claims.

It's completely subjective, which may or may not be a good thing depending on the mood of the regulator, court, and your opinion of rule by common law.