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What are they doing with all this data tracking because it sure isn't giving me relevant ads. In addition to the often noted situation where you buy something o

What are they doing with all this data tracking because it sure isn't giving me relevant ads. In addition to the often noted situation where you buy something online and then get ads for that thing you already bought, I routinely see totally irrelevant ads and recommendations. I've been on Facebook since around 2003. I've had an Amazon account for even longer. Their ads and recommendations for me are terrible. Two recent examples from facebook: they recommended I join a group for progressive christian asian-americans. I am not christian or of asian descent. More recently they gave me an ad for maximizing tax right offs for nannies. I have no children and make way too little to even consider hiring a nanny. Facebook has my picture. They know my relationship status. They have the text of all my posts where I have never mentioned children. They even know my occupation. Whatever they are doing with this data isn't working.

m463 7y ago
On relevant ads. You see ads from companies with the most to gain from getting to your eyeballs. These companies are not the ones you are interested in, who will probably get your business anyway.
DougBTX 7y ago
I wonder how much of this is a scam on the advertisers too, sure the platform might have great detail for targeting ads, but if someone comes along and outbids on generic terms it isn’t going to do you much good as an advertiser either.
- nerdponx 7y ago
  Judging from some of the comments I've seen here, quite a lot.
  - mattkevan 7y ago
    I used to lead the product team for a publisher that makes the majority of its income from ads. It was a constant fight between the commercial teams and us. Commercial wanted to stuff every page with as many ads and trackers as possible. We wanted to ensure the user didn’t have a miserable experience. As the company liked getting money, we, and the user, generally lost. I kept an instance of Chrome blocker-free to see the site in all its ad-stuffed glory, but after learning a bit about how things work, I block all the things with extreme prejudice for personal browsing. And ensure friends & family do too.
- DailyHN 7y ago
  Using Google retargeting ads, less than 5% of desktop traffic goes on to click anywhere on my website. And it's worse for mobile than on desktops. Source: I setup Google Analytics event tracking to trigger on every page click. Edit: change 10% to 5%. And it's actually only 2.5% over the past 14 days. Edit2: and that was from ~200 clicks over 14 days.
  - majewsky 7y ago
    > I setup Google Analytics event tracking to trigger on every page click. Thank you, I now feel as good as I'll ever feel about using uBO.
    - cameronbrown 7y ago
      I think tracking page clicks is completely different to invasive data profiling. Anything that could theoretically be tracked server-side (like a link click) is fair game. The only reason it's done client side is easy implementation.
    - DailyHN 7y ago
      As someone who never uses any blockers, what's the benefit to you? I imagine you have some role in building the internet since you're on HN. As far as I'm aware, by not blocking ads I am experiencing the internet that the majority of people also experience. And I think that's how I can better understand the people I build things for. Maybe if more tech workers took off their tin-foil ad-blocking hats then the ad industry, and the whole internet, would be better off. Edit: I wonder how many developers that work for ad companies also use ad blockers. Probably a lot?
      - geggam 7y ago
        I used to work for an ad company, ad blockers really dont stop the tracking. They just make the internet usable :)
        DailyHN 7y ago
kgwxd 7y ago
Relevant ads were never the goal, it's just the least creepy sounding excuse for spying.
- rfrey 7y ago
  What is the goal then, for profit seeking advertising companies like Google and Facebook?
  - kevin_thibedeau 7y ago
    Scam the advertisers.
  - lame88 7y ago
    Easy, it just means advertising doesnt cover everything. The fact that they know so much about you is valuable in itself and they can sell access to that data, for example... to cambridge analytica. Advertising is just one of the ways in which corporations exploit information to manipulate people’s behavior.
    - velp 7y ago
      Facebook never sold data to CA
      - lame88 7y ago
        Please elaborate on how i've been misinformed in this respect. I've gotten downvoted a bit without much feedback. Also, since the distinction matters, I would like to point out that I claimed selling "access to" that data, not selling the data directly.
- drdeadringer 7y ago
  > Relevant ads were never the goal That, then, is "targeted advertising" against this non-goal?
vmurthy 7y ago
I am curious given that I have an Ad-blocker for most websites and am not on FB. How do you even see ads? Have FB et al found a workaround for ad-blockers?
- Jackim 7y ago
  I have uBlock origin and I still occasionally see ads in Facebook feeds.
  - username444 7y ago
    Facebook puts a lot of time and effort into obfuscation of course code. They generate random classes and IDs and interweave containers (divs, spans, custom HTML elements) on each page load so that software can't tell what is content and what is an ad. It's actually a really neat trick.
    - Jackim 7y ago
      It is definitely impressive. But it's something that I think could be defeated pretty easily with a pretty simple machine learning model. Could be a fun project!
      - kasey_junk 7y ago
        Note that your adversary has a huge ML capability and approaching nation state resources. Careful with the terms easily & simple.
        technologic 7y ago
        lol the limit approaching nation state
    - zrobotics 7y ago
      What an absolute shame that they waste the time of all their highly-skilled developers on garbage like that. The user has specifically indicated, by running an ad-blocker, that they aren't interested in being marketed to. At least for me, ads that bypass my blockers really irritate me, to the point that whatever company was unfortunate enough to win that bid actually hurts themselves as I will be more likely to select a competitors product.
Scoundreller 7y ago
> online and then get ads for that thing you already bought Try getting ads for the thing you just sold and needed to copy the specs into an ad.
pixelrevision 7y ago
No but if you spend a bit of time you can finesse a system. I’ve been not using Facebook for a while but a few years ago I noticed they had “likes” and “see more of this” so I liked as much Cthulhu related ads as I could find and my ads pretty quickly looked like they were being served from carcosa. I suspect that we will not ever see all this information actually give us better ads. The people in charge of this sort of stuff typically just want to get more clients so they are happy to inflate. The problem I see is that there is a whole lot of personal data being sent around all over the place to fly by night companies with no incentive to protect it.
xfitm3 7y ago
Ad targeting is intentionally fuzzy to avoid creeping you out. Companies like Acxiom have an incredible amount of data on you. https://www.forbes.com/sites/kashmirhill/2012/02/16/how-target-figured-out-a-teen-girl-was-pregnant-before-her-father-did/#2b42b4aa6668 https://www.forbes.com/sites/kashmirhill/2012/02/16/how-targ...
- pessimizer 7y ago
  A friend of mine worked for Acxiom, and when they looked themselves up they found 6-7 different profiles, all fantastically wrong, some clearly mixed with information from other people. Admittedly it's a very private person that I'm talking about who deliberately obscures themselves by leaving incorrect or misspelled information when forced to give any information, and who moves, switches jobs often, has an odd name, and changed that odd name through marriage. But I think that a lot of us are falling for the marketing of these intelligence companies, rather than judging them by predictive effectiveness because we don't have any access to that. There's no real theory of mind behind all of this stuff; it seems to be that it will only ultimately be effective for creating black/whitelists where you don't care about a lot of false positives.
  - cameronbrown 7y ago
    Terrifying that, even if they're looking up themselves, they're seeing other people's private data..
  - luckylion 7y ago
    > A friend of mine worked for Acxiom, and when they looked themselves up they found 6-7 different profiles, all fantastically wrong, some clearly mixed with information from other people. With my tin foil hat on tight, maybe they create shitty profiles on all their employees so they don't get freaked out and run for the hills!
    - NetOpWibby 7y ago
      That’s a tight hat, I think I own the same one.
stareatgoats 7y ago
Facebook doesn't send you the ads, advertisers do. And they are (usually) terrible at segmenting.
mihaifm 7y ago
Watched some Youtube yesterday, it kept showing me the same freaking ad for like 20 times in a row. Sometimes I get the same 2-3 ads for weeks at a time. Not sure what's the idea, if you're going to show ads at least make it a barable experience, it's almost as if they're trying to trigger some breaking point.
- jccalhoun 7y ago
  If I see an add for Good Omens while trying to watch something on twitch on my tv I am going to flip a table.
- parliament32 7y ago
  Same experience, it's not clear if it's just one advertiser blowing a lot of cash at once, or Google deciding I really need whatever product, but man oh man when I hit one of those ad loops it puts me off of that product forever. The most recent was Grammarly, for about a month straight 80% of the video ads Youtube showed me were the same two Grammarly ads going back and forth. I'm not sure why Google decided that I really need to fix my grammar... but I know sure as shit I'll never have anything to do with Grammarly, ever.
PaulHoule 7y ago
It amazes me that this story doesn't get more press. The press thinks that Outbrain and Tabooleh are such geniuses, but they show the same ads they've shown for five years that everyone I know has learned not to click on. (e.g. if you do click on one promising to see some kind of images the one image you won't see when you click is what is promised.)
username444 7y ago
Facebook isn't targeting you. The advetisers are. Facebook's real sin is a garbage UI meant to confuse advertisers into spending money on audiences that don't align with the advertiser. Google is much, much worse with this. The bid system means that the Christian Asians didn't do a good targeting job, and nobody else found you valuable enough to bid on, so the Christian Asians won the bid. You got served a penny ad because nobody else wanted to show you one.
- rrrx3 7y ago
  I work in Ad Tech. This is on target. The user was lumped into a poorly-constructed lookalike audience because of some stretched interest similarities. What you're experiencing is the confluence of two distinct issues: 1. The CTRs on digital advertising are dropping YoY. People DO NOT click on ads, even if they are saliently targeted. There are enough trash ads out there, there's so much malware and malfeasance in the ecosystem, that it's worthwhile for users to at best _ignore_ and at worst (for advertisers) _to block ads totally_. 2. The desire to target people that match specific criteria is rising because of misguided notions throughout the advertising and marketing industry. This has driven the entire industry to push machine learned modeling to find each and every set of eyeballs out there to try and justify spend, instead of offering worthwhile and valuable offers that compel consumers to interact. You have entire systems constructed on the notion that the more people you get an ad in front of, the more valuable it is, and agencies and trading desk operators that are looking at this as the sole KPI to focus on, to the detriment of everyone involved.
  - jimbob45 7y ago
    It sounds like what you're saying is that online ads are becoming less and less effective due to customers getting trained to ignore/block ads. However, companies are responding by attempting to improve their ad targeting instead of facing the reality that online ads aren't effective anymore. What will happen in five years when advertisers have to face the reality through numbers that online ads don't work anymore?
    - 7y ago
55555 7y ago
Facebook makes the data available to advertisers who are then responsible for targeting you well based on that data. If the advertiser makes terrible targeting decisions but offers a high bid for a click, then despite your low CTR and low conversion rate, you'll see the ad. Facebook is not choosing which ads you see. (The recommendations, sure.)
- Theodores 7y ago
  I think the technical term for these ads that stalk you after you have bought the product is 'remarketing'. Amazon should know what they are doing but they do the ads of what you have just bought, even though they have good information. No idea what their excuse is for fluffing it. However, with small companies, e.g. a clothes shop, they don't do the website necessarily themselves, getting an agency to do it. When they get to a certain size they bring this work on house, but the principles of cock up are the same, in the agency or in house. The agency doing the website have extra add on services for SEO, remarketing and other marketing snake oil. The people in these jobs are not the sort that can do database joins. They use products that have been marketed at them and generally work on second hand hearsay to determine what works, even though they do use graphs and data. They are not necessarily going to know the products and even though they buy adverts they do not see themselves as in the advertising game, more in the marketing field. The internet has raised everyone's boats over the last few years so these people can have some legit upward pointing graphs, what is less clear is whether it is demand, price or product that has got their clients online sales up. However, they can claim it is all their work and that the campaigns they have put on have changed something assumed to be static. On this snake oil they can attract new clients to bring them marketing spend. They try their hardest but they are not data power users. I know that is tarring a whole industry with the same brush, but the people in this industry will be 'power Excel users' rather think to become 'novice SQL users'. To be honest logging in to some of these Facebook account screens is quite hard work, going through the right channels to get the login details from the client can take all day. Uploading data probably needs help from a developer on a different team, plus you have to go home at 5.30 on the dot. People that are good at selling product believe in customer service, word of mouth, product and a multitude of things that are a million miles away from remarketing. So the industry of online ad sales invariably has hit and miss results because the people in the business are unlikely to be that smart.
the_watcher 7y ago
Just curious, did you go to Harvard with Zuck? That's the only way you could have been on Facebook that long, as he only created the earliest version in fall 2003.
- jccalhoun 7y ago
  I just checked. It looks like my earliest post was in October of 2007. Sorry!
adrianmonk 7y ago
It seems like a fundamentally difficult problem to know when you've already bought something. Obviously, it's solvable in simple cases, like when you browse and buy from the same vendor. But in other cases, it's not, like if you browse around multiple places and buy from one, or if you look around online and buy in person. Basically, the information that you're interested in buying is going to spread around to certain places, and the information that you've bought is also going to spread around, but there is nothing to guarantee that it will percolate to all the same places. You also have to consider the trade-off an advertiser faces. They'd probably rather show an irrelevant (already bought) ad than miss a chance to show a relevant one to someone who is still actively shopping. So they'd probably choose to err on that side.
- newsoul2019 7y ago
  Amazon knows. Google knows too, if your Amazon emails went to your Gmail account. Your credit card company has a good idea of who you bought from, but not what.

m463 7y ago

On relevant ads. You see ads from companies with the most to gain from getting to your eyeballs. These companies are not the ones you are interested in, who will probably get your business anyway.

DougBTX 7y ago

I wonder how much of this is a scam on the advertisers too, sure the platform might have great detail for targeting ads, but if someone comes along and outbids on generic terms it isn’t going to do you much good as an advertiser either.

nerdponx 7y ago
Judging from some of the comments I've seen here, quite a lot.
- mattkevan 7y ago
  I used to lead the product team for a publisher that makes the majority of its income from ads. It was a constant fight between the commercial teams and us. Commercial wanted to stuff every page with as many ads and trackers as possible. We wanted to ensure the user didn’t have a miserable experience. As the company liked getting money, we, and the user, generally lost. I kept an instance of Chrome blocker-free to see the site in all its ad-stuffed glory, but after learning a bit about how things work, I block all the things with extreme prejudice for personal browsing. And ensure friends & family do too.
DailyHN 7y ago
Using Google retargeting ads, less than 5% of desktop traffic goes on to click anywhere on my website. And it's worse for mobile than on desktops. Source: I setup Google Analytics event tracking to trigger on every page click. Edit: change 10% to 5%. And it's actually only 2.5% over the past 14 days. Edit2: and that was from ~200 clicks over 14 days.
- majewsky 7y ago
  > I setup Google Analytics event tracking to trigger on every page click. Thank you, I now feel as good as I'll ever feel about using uBO.
  - cameronbrown 7y ago
    I think tracking page clicks is completely different to invasive data profiling. Anything that could theoretically be tracked server-side (like a link click) is fair game. The only reason it's done client side is easy implementation.
  - DailyHN 7y ago
    As someone who never uses any blockers, what's the benefit to you? I imagine you have some role in building the internet since you're on HN. As far as I'm aware, by not blocking ads I am experiencing the internet that the majority of people also experience. And I think that's how I can better understand the people I build things for. Maybe if more tech workers took off their tin-foil ad-blocking hats then the ad industry, and the whole internet, would be better off. Edit: I wonder how many developers that work for ad companies also use ad blockers. Probably a lot?
    - geggam 7y ago
      I used to work for an ad company, ad blockers really dont stop the tracking. They just make the internet usable :)
      - DailyHN 7y ago

kgwxd 7y ago

Relevant ads were never the goal, it's just the least creepy sounding excuse for spying.

rfrey 7y ago
What is the goal then, for profit seeking advertising companies like Google and Facebook?
- kevin_thibedeau 7y ago
  Scam the advertisers.
- lame88 7y ago
  Easy, it just means advertising doesnt cover everything. The fact that they know so much about you is valuable in itself and they can sell access to that data, for example... to cambridge analytica. Advertising is just one of the ways in which corporations exploit information to manipulate people’s behavior.
  - velp 7y ago
    Facebook never sold data to CA
    - lame88 7y ago
      Please elaborate on how i've been misinformed in this respect. I've gotten downvoted a bit without much feedback. Also, since the distinction matters, I would like to point out that I claimed selling "access to" that data, not selling the data directly.
drdeadringer 7y ago
> Relevant ads were never the goal That, then, is "targeted advertising" against this non-goal?

vmurthy 7y ago

I am curious given that I have an Ad-blocker for most websites and am not on FB. How do you even see ads? Have FB et al found a workaround for ad-blockers?

Jackim 7y ago
I have uBlock origin and I still occasionally see ads in Facebook feeds.
- username444 7y ago
  Facebook puts a lot of time and effort into obfuscation of course code. They generate random classes and IDs and interweave containers (divs, spans, custom HTML elements) on each page load so that software can't tell what is content and what is an ad. It's actually a really neat trick.
  - Jackim 7y ago
    It is definitely impressive. But it's something that I think could be defeated pretty easily with a pretty simple machine learning model. Could be a fun project!
    - kasey_junk 7y ago
      Note that your adversary has a huge ML capability and approaching nation state resources. Careful with the terms easily & simple.
      - technologic 7y ago
        lol the limit approaching nation state
  - zrobotics 7y ago
    What an absolute shame that they waste the time of all their highly-skilled developers on garbage like that. The user has specifically indicated, by running an ad-blocker, that they aren't interested in being marketed to. At least for me, ads that bypass my blockers really irritate me, to the point that whatever company was unfortunate enough to win that bid actually hurts themselves as I will be more likely to select a competitors product.

Scoundreller 7y ago

> online and then get ads for that thing you already bought Try getting ads for the thing you just sold and needed to copy the specs into an ad.

pixelrevision 7y ago

No but if you spend a bit of time you can finesse a system. I’ve been not using Facebook for a while but a few years ago I noticed they had “likes” and “see more of this” so I liked as much Cthulhu related ads as I could find and my ads pretty quickly looked like they were being served from carcosa. I suspect that we will not ever see all this information actually give us better ads. The people in charge of this sort of stuff typically just want to get more clients so they are happy to inflate. The problem I see is that there is a whole lot of personal data being sent around all over the place to fly by night companies with no incentive to protect it.

xfitm3 7y ago

Ad targeting is intentionally fuzzy to avoid creeping you out. Companies like Acxiom have an incredible amount of data on you. https://www.forbes.com/sites/kashmirhill/2012/02/16/how-target-figured-out-a-teen-girl-was-pregnant-before-her-father-did/#2b42b4aa6668 https://www.forbes.com/sites/kashmirhill/2012/02/16/how-targ...

pessimizer 7y ago
A friend of mine worked for Acxiom, and when they looked themselves up they found 6-7 different profiles, all fantastically wrong, some clearly mixed with information from other people. Admittedly it's a very private person that I'm talking about who deliberately obscures themselves by leaving incorrect or misspelled information when forced to give any information, and who moves, switches jobs often, has an odd name, and changed that odd name through marriage. But I think that a lot of us are falling for the marketing of these intelligence companies, rather than judging them by predictive effectiveness because we don't have any access to that. There's no real theory of mind behind all of this stuff; it seems to be that it will only ultimately be effective for creating black/whitelists where you don't care about a lot of false positives.
- cameronbrown 7y ago
  Terrifying that, even if they're looking up themselves, they're seeing other people's private data..
- luckylion 7y ago
  > A friend of mine worked for Acxiom, and when they looked themselves up they found 6-7 different profiles, all fantastically wrong, some clearly mixed with information from other people. With my tin foil hat on tight, maybe they create shitty profiles on all their employees so they don't get freaked out and run for the hills!
  - NetOpWibby 7y ago
    That’s a tight hat, I think I own the same one.

stareatgoats 7y ago

Facebook doesn't send you the ads, advertisers do. And they are (usually) terrible at segmenting.

mihaifm 7y ago

Watched some Youtube yesterday, it kept showing me the same freaking ad for like 20 times in a row. Sometimes I get the same 2-3 ads for weeks at a time. Not sure what's the idea, if you're going to show ads at least make it a barable experience, it's almost as if they're trying to trigger some breaking point.

jccalhoun 7y ago
If I see an add for Good Omens while trying to watch something on twitch on my tv I am going to flip a table.
parliament32 7y ago
Same experience, it's not clear if it's just one advertiser blowing a lot of cash at once, or Google deciding I really need whatever product, but man oh man when I hit one of those ad loops it puts me off of that product forever. The most recent was Grammarly, for about a month straight 80% of the video ads Youtube showed me were the same two Grammarly ads going back and forth. I'm not sure why Google decided that I really need to fix my grammar... but I know sure as shit I'll never have anything to do with Grammarly, ever.

PaulHoule 7y ago

It amazes me that this story doesn't get more press. The press thinks that Outbrain and Tabooleh are such geniuses, but they show the same ads they've shown for five years that everyone I know has learned not to click on. (e.g. if you do click on one promising to see some kind of images the one image you won't see when you click is what is promised.)

username444 7y ago

Facebook isn't targeting you. The advetisers are. Facebook's real sin is a garbage UI meant to confuse advertisers into spending money on audiences that don't align with the advertiser. Google is much, much worse with this. The bid system means that the Christian Asians didn't do a good targeting job, and nobody else found you valuable enough to bid on, so the Christian Asians won the bid. You got served a penny ad because nobody else wanted to show you one.

rrrx3 7y ago
I work in Ad Tech. This is on target. The user was lumped into a poorly-constructed lookalike audience because of some stretched interest similarities. What you're experiencing is the confluence of two distinct issues: 1. The CTRs on digital advertising are dropping YoY. People DO NOT click on ads, even if they are saliently targeted. There are enough trash ads out there, there's so much malware and malfeasance in the ecosystem, that it's worthwhile for users to at best _ignore_ and at worst (for advertisers) _to block ads totally_. 2. The desire to target people that match specific criteria is rising because of misguided notions throughout the advertising and marketing industry. This has driven the entire industry to push machine learned modeling to find each and every set of eyeballs out there to try and justify spend, instead of offering worthwhile and valuable offers that compel consumers to interact. You have entire systems constructed on the notion that the more people you get an ad in front of, the more valuable it is, and agencies and trading desk operators that are looking at this as the sole KPI to focus on, to the detriment of everyone involved.
- jimbob45 7y ago
  It sounds like what you're saying is that online ads are becoming less and less effective due to customers getting trained to ignore/block ads. However, companies are responding by attempting to improve their ad targeting instead of facing the reality that online ads aren't effective anymore. What will happen in five years when advertisers have to face the reality through numbers that online ads don't work anymore?
  - 7y ago

55555 7y ago

Facebook makes the data available to advertisers who are then responsible for targeting you well based on that data. If the advertiser makes terrible targeting decisions but offers a high bid for a click, then despite your low CTR and low conversion rate, you'll see the ad. Facebook is not choosing which ads you see. (The recommendations, sure.)

Theodores 7y ago
I think the technical term for these ads that stalk you after you have bought the product is 'remarketing'. Amazon should know what they are doing but they do the ads of what you have just bought, even though they have good information. No idea what their excuse is for fluffing it. However, with small companies, e.g. a clothes shop, they don't do the website necessarily themselves, getting an agency to do it. When they get to a certain size they bring this work on house, but the principles of cock up are the same, in the agency or in house. The agency doing the website have extra add on services for SEO, remarketing and other marketing snake oil. The people in these jobs are not the sort that can do database joins. They use products that have been marketed at them and generally work on second hand hearsay to determine what works, even though they do use graphs and data. They are not necessarily going to know the products and even though they buy adverts they do not see themselves as in the advertising game, more in the marketing field. The internet has raised everyone's boats over the last few years so these people can have some legit upward pointing graphs, what is less clear is whether it is demand, price or product that has got their clients online sales up. However, they can claim it is all their work and that the campaigns they have put on have changed something assumed to be static. On this snake oil they can attract new clients to bring them marketing spend. They try their hardest but they are not data power users. I know that is tarring a whole industry with the same brush, but the people in this industry will be 'power Excel users' rather think to become 'novice SQL users'. To be honest logging in to some of these Facebook account screens is quite hard work, going through the right channels to get the login details from the client can take all day. Uploading data probably needs help from a developer on a different team, plus you have to go home at 5.30 on the dot. People that are good at selling product believe in customer service, word of mouth, product and a multitude of things that are a million miles away from remarketing. So the industry of online ad sales invariably has hit and miss results because the people in the business are unlikely to be that smart.

the_watcher 7y ago

Just curious, did you go to Harvard with Zuck? That's the only way you could have been on Facebook that long, as he only created the earliest version in fall 2003.

jccalhoun 7y ago
I just checked. It looks like my earliest post was in October of 2007. Sorry!

adrianmonk 7y ago

It seems like a fundamentally difficult problem to know when you've already bought something. Obviously, it's solvable in simple cases, like when you browse and buy from the same vendor. But in other cases, it's not, like if you browse around multiple places and buy from one, or if you look around online and buy in person. Basically, the information that you're interested in buying is going to spread around to certain places, and the information that you've bought is also going to spread around, but there is nothing to guarantee that it will percolate to all the same places. You also have to consider the trade-off an advertiser faces. They'd probably rather show an irrelevant (already bought) ad than miss a chance to show a relevant one to someone who is still actively shopping. So they'd probably choose to err on that side.

newsoul2019 7y ago
Amazon knows. Google knows too, if your Amazon emails went to your Gmail account. Your credit card company has a good idea of who you bought from, but not what.