Ask HN: How does Facebook know what I buy on Amazon or vice versa?
Following just happened: An hour before lunch I googled and visited websites that sell bicycles. I also visited Amazon during this research. I then bought a bike from one of the manufacturers' websites. A few hours later I browse facebook and see ads to this manufacturers' bikes in my newsfeed, via an Amazon sponsored ad.
I use one browser (Safari) for facebook exclusively, and browsed the bikes / Amazon / made the purchase on Chrome. I have different email addresses for facebook, amazon and, well, google.
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[ 3.0 ms ] story [ 105 ms ] threadThe other possibility is that your multiple email addresses have been matched as the same person. So even though you use different browsers and have different cookies, they're collapsed on Facebook's side.
More info here[2]
1: https://www.amazon.com/adprefs?ref_=ya_advertising_preferenc...
2: https://www.usatoday.com/story/tech/columnist/2017/02/12/how...
You go to Amazon, they tell Facebook what you are looking at, and then can dynamically create ads specifically for you.
An effective ad network would know that OP already bought such a bike, so it's actually useless to try to sell him bikes... maybe accessories.
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-pollute between browsers / devices / etc the signal is picked up and then compared with browsing behavior etc to get a strong profile. (1)
(1) https://www.facebook.com/business/a/performance-marketing-st...
> 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.
https://www.youtube.com/watch?v=JI8AMRbqY6w
I'd figure it's more about getting paid. Making the world better usually doesn't make anyone money, or at least, costs too much before it starts making anyone money.
Making the world truly better requires us to give up a lot of what gets ingrained into us since childhood. We've made money an ends instead of a means. I'm not making a political statement – this is true of every human society, culture and country today. We should collectively rethink what it means to be a successful human and have a fulfilling life (without abandoning technology and progress.)
What's the end goal of civilization? Are we to just multiply and expand, ad infinitum?
>I'd figure it's more about getting paid. Making the world better usually doesn't make anyone money, or at least, costs too much before it starts making anyone money.
This. I get paid (a lot) for handling marketing campaigns. I also started a health project this year (would love to work on it fulltime on a 10% payment vs what I make now), but that gets ignored.
Excerpt From: King, Stephen. “Different Seasons.”
When writing ad targeting code, user surveillance, nuclear missile guidance, VW pollution test circumvention code... you know exactly what is going on.
This is usual network security.
At some point someone need to glue together existing devices and software into something that has an obvious use case with ethical implications e.g. the chinese "great firewall".
Where does this take us though? If you build a bridge, how do you know what will go across it? Either we all stop or we accept that not all ethical questions can be resolved by individuals acting alone.
We live in a capitalist society.
It just so happens that this "gross technology" makes advertising insanely profitable for millions of companies (mine included), which makes FB billions, so they'll happily pay really smart people millions to build it. And those smart people will happily accept millions to solve those hard problems.
It's just business. If you can figure out how to better align individual and corporate incentives with making the world a better place, we're all ears.
Always a solid cop-out for allowing bad things to continue
How many people do go into computer engineering with an idea of making the world a better place?
Don't misunderstand me, I'm sure many computer engineers are nice, socially conscious people, but if your primary motivation in life is to make the world a better place through your work, there are many more direct ways to achieve this.
It's telling that the Gates Foundation, which has enormous resources, and which could build, should it so wish, the world's best-funded 'change the world with code' startup, instead chooses to allocate its resources on physical things such as malaria drugs.
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.
Perhaps the coming A.I.pocalypse™ will give us better predictive suggestion algorithms before turning on us... Or the sentient networks just start recommending really dangerous products to wipe ourselves out with! ;(
Chatting with friends, I've discovered FB are also really, really good at showing me adverts for what other people are buying my chums for Xmas, which is of limited use frankly.
Not really technical friend gets a smarthpone. We check specs on gsmarena, then check few other phones, read a bit more. Lots of hits over short time. Ad targeting: you must be searching for a smartphone, here get some ads for smartphones! I check various pages over few weeks, compare phones, check availability. Ad targeting: very rare hits, must be accidental.
For the past few weeks I have been selecting a pair of products. Watching youtube, reading various forums, browsing manufacturer pages, browsing stores, comparing prices, usual stuff. A single ad for at least one of those two product categories? Nope, instead I see ads to subscribe to my current carrier.
To actually track checkouts/purchases correctly so that you don't advertise to those people requires a completely different setup.
And they of course get to repeat the name of the store for you so that you're more likely to think of them the next time you need a related product, even if it's not a basketball. You'll remember that you've seen the name of store X in multiple places, so they must be popular.
http://net.ipcalf.com/
The media device IDs the browsers provide look even worse:
https://jsfiddle.net/u4n4s296/
I am not sure if these are unique to the device type (for example a certain soundcard model) or to the device itself. If it's the latter, then that is an indestructible cross-browser cookie right there. EDIT: As per icebraining's comment, in Firefox they are not not cross-domain, not cross-browser and get randomized when you delete your cookies.
https://developer.mozilla.org/en-US/docs/Web/API/MediaDevice...
Safari (tech preview or high sierra) seems to give a new value every time you reload the page.
They segment users that visited each product on Facebook with a custom audience and then create ads for similar products that they show you. This is all done programmatically.
Amazon is different to other AD buyers. Amazon does not want FB to know what customers are doing on its own site, so there is no FB tracker on Amazon at all. However, Amazon can choose what ad to deliver to you on FB backed up by its own team.
If one logged into Amazon in both browsers then it is really just linking to the account (even after logging out).
It's not Facebook tracking you, it's Amazon.
It's also not Facebook giving you the ad, it's Amazon. So technically not a privacy violation.
you know, incase you find this kind of thing reprehensible.
For some reason it picked up the kid who stocks the craft beer at my local family run grocer. Literally only talked to the kid face-to-face. No phone number, no texting, no contact entry (not that I share those with Facebook anyways).
That made the hair on the back of my neck stick up when that happened.
I had a similar situtation where Facebook recommended that I friend a coworker that sat next to me.
The situation I described happened over a year ago, so I imagine they were using location data then.
Based on the high intersection of two sets of SSIDs names visible from two devices at the same time, you can decide two people were in one room together. If this happens regularly, you can be quite confident people "know" each other in some way, which can unveil many surprising "friends" recommendations.
I know this because you can browse for something on Amazon on one machine, then find ads for that item on an entirely different machine - but one that's using the same WiFi.
Good luck buying a surprise present for a Significant Other. If you try, they'll see ads for it on Facebook.
I've never had an FB account and they seem to know it.
Well, I guess ad companies have no idea how much money I make.
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 inconvenient. These DMPs work off statistics, so they don't need to know 100% that this browser session is probably kmonad, just 70%. Maybe you have the same IP, OS version, browser extensions, cookie sets...
Basically, there are a bunch of methods for tying your session back to your identity, and most DMPs will run through a good dozen or two. Most will fall back on geolocation patterns (which are surprisingly accurate themselves) but it's actually very hard to totally anonymize your internet activity. We are creatures of habit, but our patterns betray us. :)
On the contrary, I'd wager that a person who's purchased a bike is far more likely to buy another than a random other person. I'm not saying there's isn't someone more likely to buy one than the guy who just did. But he would be more likely than someone who has no recent bike related purchases or interest.
It could be as simple as, "Hey this is a nice bike I bought. I bet my wife/sister/brother/friend would like one too. Hey Bike Co is having a sale!".