Ask HN: Why do I see ads about what I read/write on my offline laptop?

[silent_speech]

I have an old laptop loaded with an offline copy of Wikipedia (Kiwix). It has no networking whatsoever and hasn't seen an USB device for more than a year. I use it daily to read as I would a physical encyclopedia and I take some notes on it that never leave (or so I guessed).

I also have a Pixel phone and accounts on all major social media. So I have noticed recently that after reading on that laptop about cookies, I get ads of cookie brands. Cats lead to cat food ads. Vitamins lead to supplement ads. Companies and businesses lead to job offer ads from the respective ones. It is very blatant and immediate.

Is data leaking from that system to advertisers? How?

[norhi999]

Looks like a typical case of Baader–Meinhof phenomenon* to me.

* https://en.wikipedia.org/wiki/Frequency_illusion

[ChrisGranger]

I nearly posted exactly this, but was wondering if a single instance of a thing [I read about cats and then saw an ad about cats] would be enough to qualify. I agree that it does sound like a subjective bias and would need to know how many ads are seen that don't ring the bell.

[zw123456]

I have had that similar feeling and have joked around that Amazon is reading my mind. I go outside and see bird poo on my deck and driveway and they send me an add for a pressure washer. Wow, how did they do that, ESP? It sure feels like it, but no, they know I own a home (based on previous purchases, perhaps other things, but really they can tell by what I have bought before). It's spring, and what do homeowners do in the spring ? they pressure wash their decks. They send me adds for other spring home related things. But it sort of felt creepy for a minute until I thought about it.

[silent_speech]

Asked question, went to sleep, woke up to both the laptop and Pixel phone crashed to the bootloader and failing to load their operating system. Guess I probed a weak spot by posing a question. Thank you all for the answers, albeit I am leaning towards it being something else.

[car_analogy]

Could it be the other way around? You read about cookies online, which prompts you read about them offline too, and causes the ads.

I.e. both your offline activity and ads are caused by preceding online activity?