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Ask HN: How does Facebook know what I buy on Amazon or vice versa?

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Re: Ask HN: How does Facebook know what I buy on Amazon or vice versa?

#51

Post by mateo411 »

beejiu wrote: post #37
mateo411 wrote: post #32

Earlier quoted context omitted.

There is some process that is running a spatial join. You were both logged into facebook at the same time, and were in close proximity. I had a similar situtation where Facebook recommended that I friend a coworker that sat next to me.

Facebook claimed a year ago that they did not use location data. https://www.theguardian.com/technology/2016/jun/29/how-does-...

Interesting.

The situation I described happened over a year ago, so I imagine they were using location data then.

Re: Ask HN: How does Facebook know what I buy on Amazon or vice versa?

#52

Post by NTDF9 »

md224 wrote: post #44
aresant wrote: post #8

Straightforward: 1) Amazon tracked your research and likes to use " ad retargeting" if they see you leave before checking out to remind you to come back and purchase. 3) FB offers advertisers a variety of retargeting means + insanely advanced cross-device tracking. Like a building full of PhD's advanced. Maintaining privacy by logging in from different devices / accounts / etc is a thing of the past if you EVER cross…

But... what about step 2? > Like a building full of PhD's advanced. On a more serious note, it's unfortunate that so many smart people use their intelligence to enable this kind of gross technology. It's all about "solving puzzles" rather than making the world a better place. There's gotta be more productive ways to advance your career.

Whatever made you think that tech industry is a beacon symbolizing all the good things about humanity!

Re: Ask HN: How does Facebook know what I buy on Amazon or vice versa?

#53

Post by hossbeast »

calebcuster wrote: post #33

If you want to know what advertisers are retargeting you, you might want to check: http://whoisretargeting.me It can be enlightening. You can also opt out of a lot of it here: https://www.facebook.com/help/568137493302217

Does not work under Brave - which means I'm protected from retargeting, too?

Re: Ask HN: How does Facebook know what I buy on Amazon or vice versa?

#54

Post by [deleted] »

md224 wrote: post #44
aresant wrote: post #8

Straightforward: 1) Amazon tracked your research and likes to use " ad retargeting" if they see you leave before checking out to remind you to come back and purchase. 3) FB offers advertisers a variety of retargeting means + insanely advanced cross-device tracking. Like a building full of PhD's advanced. Maintaining privacy by logging in from different devices / accounts / etc is a thing of the past if you EVER cross…

But... what about step 2? > Like a building full of PhD's advanced. On a more serious note, it's unfortunate that so many smart people use their intelligence to enable this kind of gross technology. It's all about "solving puzzles" rather than making the world a better place. There's gotta be more productive ways to advance your career.

[deleted]

Re: Ask HN: How does Facebook know what I buy on Amazon or vice versa?

#56

Post by junkculture »

calebcuster wrote: post #33

If you want to know what advertisers are retargeting you, you might want to check: http://whoisretargeting.me It can be enlightening. You can also opt out of a lot of it here: https://www.facebook.com/help/568137493302217

Interesting. I whitelisted this site, and 2 of the 4 ads it displays on each refresh are from Facebook.

I've never had an FB account and they seem to know it.

Re: Ask HN: How does Facebook know what I buy on Amazon or vice versa?

#57

Post by hiisukun »

aresant wrote: post #8

Straightforward: 1) Amazon tracked your research and likes to use " ad retargeting" if they see you leave before checking out to remind you to come back and purchase. 3) FB offers advertisers a variety of retargeting means + insanely advanced cross-device tracking. Like a building full of PhD's advanced. Maintaining privacy by logging in from different devices / accounts / etc is a thing of the past if you EVER cross…

I love picturing a room full of PhDs developing a crazy complicated algorithmic wonderland. Their celebrations at the complexity and genius of their work probably cut short, when users are targeted with ads telling them to buy something that they just bought.

When human male user "Joe" purchases a women's bath robe 1 week before Mother's day, does he really need ads for women's bath robes for the next month? Of course I know this is nothing to do with the fault of the room full of PhDs.

Re: Ask HN: How does Facebook know what I buy on Amazon or vice versa?

#58

Post by Jasamba »

dbbk wrote: post #38
ars wrote: post #26

Earlier quoted context omitted.

It's not cookie, it happens across different browsers. It's IP based.

How could IP-based possibly work for people at places like college campuses?

They take the number of people from the same IP into account. IPs are broken down into public IPs vs private IPs based on traffic/timing of usage etc. There are research papers on this sort of feature contruction using only IPs. Cross device especially uses it extensively to be able to probabilistically ascertain if the person from your house who is checking their phone is the same person who checked smth on the Desktop computer last night based on your online timing, IPs, behaviour over the day. They can figure out, for instance, your office vs home browsing timing, interests etc with the same methods.

Re: Ask HN: How does Facebook know what I buy on Amazon or vice versa?

#59

Post by ams6110 »

aresant wrote: post #8

Straightforward: 1) Amazon tracked your research and likes to use " ad retargeting" if they see you leave before checking out to remind you to come back and purchase. 3) FB offers advertisers a variety of retargeting means + insanely advanced cross-device tracking. Like a building full of PhD's advanced. Maintaining privacy by logging in from different devices / accounts / etc is a thing of the past if you EVER cross…

But sort of silly to be advertising you for something you've already bought? They think maybe you liked the bike so much you'll buy another, but only if you see an ad?

Re: Ask HN: How does Facebook know what I buy on Amazon or vice versa?

#60

Post by lxchase »

exelius wrote: post #47

DMPs. Amazon buys (and sells) data to/from DMPs. That data can (and often does) include a hash of your credit cards, all the e-mail addresses you go by, etc. Amazon can basically buy programmable ad inventory that says "I want to show this ad for chainsaws to kmonad" and the DMP resolves who 'kmonad' is through a variety of methods. Realistically, the opsec you would need to have to avoid this would be astronomically…

This is most likely. To take it one level further, since you bought something, it can be DLX data (or Oracle now) or some other purchase-based data (from Visa or Nielsen Catalina). Facebook can ingest these as custom segments to target. For instance, I can buy a data segment of past purchasers of Giant bicycles for $1 CPM that will be layered on whatever partner is integrated. With every "match" there will be drop off as one ID system needs to be matched with a separate ID system (i.e. FB DLX, or Liveramp Mobile App)
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