[vbsteven]

I don’t think Google linked the account directly to the purchase. My guess would be that Google linked the account to the medication based on patterns from one of its many ways it gathers data.

* visits to websites about that medication

* visits to websites talking about symptoms for which the medication helps

* searches for the above

* I would not be surprised if Google picks up interests from other accounts using the same WiFi (or even other devices on close proximity)

* there are some scary stories about Google/FB/Amazon listening to conversations

[muzani]

I do most searches in an incognito window so it can't be browser history.

In some cases, it's even something like my wife joking about selling the car to a friend on WhatsApp, and suddenly Facebook show ads where you can sell the car. One time I told my wife to buy something at the grocery store (verbally, no text) and FB shows me the ad for that exact item.

[vbsteven]

> I do most searches in an incognito window so it can't be browser history.

Incognito mode is mostly a convenience for you to do browsing without saving local history or cookies. It doesn't stop tracking.

I assume the fingerprint is different in incognito versus a regular window. But unless you are using VPN/adblockers/pihole/etc your browser is still executing third party JS and potentially sending tracking data to google using a plain https connection coming from your residential IP.

I can imagine it's not that hard for Google to link different requests from the same IP with slightly different fingerprint data to be coming from the same user.

edit: and for searches it is even easier, because you are communicating directly with google by performing the search, no tracker or JS necessary.

[xtracto]

We had a similar thing happening to us: Wife and I have no kids and have no plans to have them. Kid related stuff is just not part of our everyday interactions. One day we visit some friend who are a couple with kids and in that visit we TALK about babies and rising kids and whatnot. Next day my wife (who has the FB app Installed), starts getting kid's diapers ads. I dont have FB app and I dont get those ads.

She uninstalled the app after that.

[vsl]

Anecdotes like this are plausibly explained as https://en.m.wikipedia.org/wiki/Frequency_illusion

[whimsicalism]

So, then, completely different from what the GP suggested.

[vbsteven]

My comment was an expansion on GPs second bullet point. It’s not Google that knows about the purchase, but Google that “somehow” picked up contextual info from OPs environment linking OPs online identity to Voltaren as a product.

Edit: the purchase could have been involved somewhere in the chain but it’s not necessary.

[whimsicalism]

> Your purchase landed some key about you in a bucket that was mixed and repackaged with many other keys that the advertiser knows as "keys recently interested in Voltaren."

There's not really that much ambiguity in this sentence from the second bullet point.

Unless my mental model of online advertising is wrong, your physical in-store purchase should not be landing you in some Google advertising bucket.

[vbsteven]

I completely agree that they should not show up. It looks like I went lightly over that sentence and focussed more on the one after:

> Some of those keys are related to people who bought it, or who searched for it, or more indirectly who lingered while reading a page with an ad for it...and in most cases are very short lived.

[nextos]

I think it's the last option. His phone probably heard him ordering Voltaren. It's also the simplest possibility (Ockham's razor).

I know because after discussing extremely rare chemicals at an officemate's desk, he began seeing ads for them. Neither of us had ever Googled or emailed anything related. It was a brand new idea for a brand new project which we had started working on that morning.

[planb]

This is not the simplest possibility. Based on how often Google Home misunderstands the simplest queries, the tech is nowhere close to getting purchase intents out of random conversations. Besides that - do folks on hn really believe the „our phones are listening 24/7“ conspiracy theories?

[planb]

I scrolled down further in the thread and it seems they do...

[6510]

We don't want to believe but here we are. [ha, ha] Our robotic overlords don't even need to be sure, sounds-like is good enough, apply some exotic filters and odds to sell things go though the roof.

My funniest was talking with someone at work (who works for a different company) then when I got home facebook suggested adding them. That I didn't have a phone at the time made it extra comical. Plenty of other people work there, it never suggested those and there are no common contacts. How the CONSPIRACY works exactly I have no idea, the candidate theories are all to hard to imagine. (Like, I'm easy to track because I have no phone?)

[NoPie]

I believe it is very possible.

My android phone often asks how did I like this or that shop. Sometimes I was just passing by those shops but on average the phone is quite correct which shops I have visited.

Google knows when you are in the pharmacy and might use a different routine interpreting ambient sounds when you are there. Voltarol (ibuprofen gel) is a distinct sound that even very lossy algorithm with low level of processing power can distinguish with a sufficient level of accuracy.

[nexuist]

Can you prove neither of you Googled anything related? Surely either you or your office mate could have done further research later on, which would involve searching those chemicals online and browsing Web pages related to them?

Alternatively if someone near you overheard your conversation, and Googled it, then Google could link all of your locations together and conclude that you are all interested in the same thing. This is how Facebook has its creepy ability to indirectly predict what items you are interested in - usually someone near you searches for what you're talking about later on in the day, and it guesses that it's important to both of you.

[xbar]

Agreed.