[blackhaz]

Just recently my wife came back home telling me about some tablet computer she has never ever seen before. I think she has googled for it on her phone. What do you know - my Facebook showed a few ads of that device - on that day. I've never heard about it before. I never searched for it and I never searched for a tablet even - I don't use them. Is this now the new normality - palantiring through databases? Is it OK for Google to leak data to Facebook?

[majormajor]

You and your wife's phones are almost certainly tied together in multiple databases that adtech companies (especially the quieter tiers below Google/FB themselves) maintain and sell. And then you get re-targeted for ads you or her see, or ads based on things you or her see (retargeting was a really big thing back when I was in the industry, since behavioral prediction wasn't quite living up to the hype - so just re-show stuff you already think is relevant! I'm sure you've seen stuff like "here's thirty other lightbulbs" after you buy one lightbulb on Amazon in the past decade.)

Here's how it worked ~12 years ago: At some point you almost certainly have used the same home internet connection. A cookie associated with some account(s) of hers gets associated with that IP. Same for some account(s) of yours. Find IPs that over small time frames only have a handful of distinct users to filter out coffeeshops and such. Bam, likely family or roommate connection. Some sticky "supercookie" stuff or similar gets set so this can be both resurrected even when cookies expire (through like Etag cache headers or whatever) and then there's a lot of behind-the-scenes ad network offline-cookie-syncing.

One of the companies in that web partners offers ads on FB, another runs ads on Google, she searches and click something on your wife's phone (at this point regardless of network), it gets tied to you too.

It could be more innocuous but tracking same-household, cross-device for retargeting... all that is really old hat at this point.

I intentionally moved my career pretty far from ad-tech in the past decade, but from what I've heard in adjacent convos and such is that the newer developments include some of the newer platforms like smart TVs into all that old cross-device fun, too. Both as data source and ad display destination. A lot of TVs phone home about what you watch, even - like https://clinch.co/clinch-partners-with-samsung-ads/ There's a million ad-tech companies out there, they aren't all just writing real-time-bidding algorithms for traditional display ads.

[honzabe]

This is really interesting. I would buy a short book describing and explaining this privacy-related stuff the way you write about it.

But every time I read something like this, I am puzzled how they can have so much information and yet be so dumb. One example (but I could give you many): I like cycling and I subscribe to some cycling-related YouTube channels (Lanterne Rouge, Dylan Johnson - normal stuff, informative, bits of light humor now and then). YouTube keeps recommending me one cycling channel I absolutely hate - it is as if it was designed to piss me off. Sensationalist, negative, clickbaity titles, made up doping allegations every other post, throwing up emoticons in titles, creepy thumbnails with syringes and distorted faces. I never watch those videos, I clicked "do not recommend this channel" multiple times, now I just leave YouTube immediately every time this appears. And somehow, with all the data they have on me and all that sophisticated AI, they still have not figured it out. How? Any explanation?

[majormajor]

I never saw much at all in terms of real, taste-level, user-based personalization beyond "keep hammering them with this one thing they clicked once" retargeting.

Everything is is by aggregate. So they can put you in a bucket with a bunch of other people with a similar footprint, and if 75% of people in that bucket convert when being shown that one you hate, you get to see it too.

Low-level optimization beyond that was rare at the places I worked.

"Sneaky but obvious" was way more common. And the browsers and platform vendors kept making it harder to do certain things, so it was a constant rat race to maintain the same level of browser tracking.

[warble]

This happens to me too. I end up blocking the channels which works, no other signalling does the job.

[sirspacey]

Having worked with ad networks, publishers, and advertisers, it’s incredibly clear that ad targeting is barely this intelligent.

But the serendipity it can create is truly wild.

[majormajor]

There's nothing particularly "intelligent" in any of the stuff I described - "see common device/profile/IP/whatever, make link."

Tracking is easy, intelligent personalization is hard. But tracking alone takes a lot of constant investment with tech development and arms race and all.

[margalabargala]

There is a much less malicious explanation here.

If that tablet company had very recently begun an internet marketing campaign, across multiple ad networks, target approximately your demographic, then it's wholly reasonable that you and your wife would independently see ads for it.

[sircastor]

An analogy to what you're suggesting is that this person and their wife each drove past the same bill board at different times.

I think the thing that most people would really find tragic and scary is that we're all far more predictable and homogenous than we'd like to believe.

[brewtide]

I've always made the statement to friends and associates that google knows far more likely what I am to do 'tomorrow' than I do. Always said half in jest, and half in acknowledgement that they have been tracking to actions physically and online for.. a decade?

It's a low key way of chatting about huge datasets and the pattern matching they can provide to computers that we as individuals simply can't keep mental track of due to scale.

We are not as unpredictable as we all believe our tiny flower selves to be.

[nmilo]

I've always read comments like this and just assume it's confirmation bias on two levels:

1. Out of the 1000s of ads you see every day, at least one of them might coincidentally relate to something you talked about. You don't notice all the ads that are wildly irrelevant.

2. Even if you personally didn't have a hyper-relevant ad experience, out of the 1000s of HN readers that might comment a reply, one of them surely did. You just might be the one lucky guy that got your hyper-relevant ad of the day.

[plagiarist]

IDK, I think it is plausible they might be joining by IP or deeper connections. I've seen some ads that aren't relevant to me but are for something my partner was looking at on a different device.

[drdaeman]

It's probably simpler than this - advertiser just runs a campaign with some broad criteria (like income estimate based on IP-geolocated ZIP code) that both people in the same household fit. No surprise the same ad that one person had seen (and remembered) will be eventually shown to the other.

[adamrezich]

years ago I moved back to my hometown in South Dakota after a few years in Washington. my mom asked me to pick up some groceries for her and gave me her credit card to pay for it. I bought the groceries and, additionally, the first Red Bull I'd had in at least a year, using her credit card. within an hour, I got a notification from that one Google app thing where you answer survey questions for Play Store credit (not sure if it still exists), asking what my opinion of Red Bull was.

to reiterate:

- I had just moved halfway across the country

- this was the first Red Bull I had purchased in at least a year

- I made the purchase using a credit card other than my own, which was in no way connected to any bank account that was connected to me

- there should have been nothing connecting me to my purchase

I uninstalled the app immediately after that. sure, maybe it was some strange coincidence, but there's been far too many strange coincidences like that to make me anywhere near comfortable with this shit.

another time, years ago, I was talking to someone about how I needed to get a new pair of cheap earbuds, and within a couple hours an Amazon ad for this specific thing appeared in my Twitter timeline.

additionally, I just got married a couple weeks ago, and my wife and I immediately started seeing ads for sexual stamina tablets in our social media feeds—thanks, evil advertising apparatus, I thought I was doing okay :/

[njharman]

There's household device linking. One reason, streaming services/smart tvs want you to link phone/stream from phone. And all those services that want your phone number to verify/provide "2 factor". Yeah, they're totally not doing that to link phone and sell for future targeted ads.

There's many other ways devices can be linked, addresses of bills for instance.

[Ekaros]

Co-worker posted to company chat that they had failed to make some payments and then had got phising mail for their bank. Wondering was this linked. Later someone pointed out that phising had come before those failures. So was completely unrelated in reality.

All the conspiracy theories out of the window...