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Ask HN: How was this ad targeted to me?

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Re: Ask HN: How was this ad targeted to me?

#21

Post by mxvzr »

stygiansonic wrote: post #11
NKCSS wrote: post #3

It's called re-targeting. You can use javascript to put users into a segment and re-target that segement; it's really easy. If you use the biggest ad-exchange (AppNexus) you can be sure to reach just about anyone anywhere.

This is correct. Retargeting is one of the most valued aspects of adtech. Manufacturers website contains an iframe to the ad networks website. They signed up for this by placing JS snippet from the ad network on their site that created the iframe. This allows ad network to know that you've visited by placing cookie. Next time you visit site that shows ads from this network they can inspect cookie and show you the ret…

Although they wouldn't have used a cookie here since it is mentioned that different browsers & devices were used. It would mean that segmenting was done on the backend, maybe using a user id from a social network.

Re: Ask HN: How was this ad targeted to me?

#22

Post by netsharc »

Bedon292 wrote: post #10

Facebook doesn't need to be open in a tab for it to know it was you on that site, and you don't even need to be signed in. You and your computers are connected, even if you think you are careful. If you have ever signed into FB from home, they know that machine / ip / whatever fingerprint is you. Even after you sign out, its still out. Even if you are in ingocnito mode, its still probably you. Then you sign in to FB…

> If you have ever signed into FB from home, they know that machine / ip / whatever fingerprint is you. Even after you sign out, its still out.

Even if you signed out, they probably still have a cookie tracking who you are, and when your browser fetches that Like button, it will still send that cookie to the Facebook server. It'd be interesting on a shared computer where 2 people (e.g. a brother and sister) log in to FB alternatively, but I guess they can still distinguish who is who (e.g. person visits gaming forum, person visits this product page, person visits page with pics of a female supermodel: presumably it's the brother visiting all 3 sites. It's a bit sexist but that's what the algorithm would guess.)

Re: Ask HN: How was this ad targeted to me?

#24

Post by sundaeofshock »

masukomi wrote: post #19
sundaeofshock wrote: post #15

The answer is cookies. Facebook sets multiple cookies on your browser that do not expire and are not deleted when you logout. By logging in at work and home, you are making it trivial for them to track you. They also set this cookie when you intract with a Facebook like, share, comment or use Facebook to log-in to a third-party site. A few suggestions to help mitigate this: - Use a browser dedicated to all your socia…

i assure you, that you can still be tracked without cookies. It's not as easy, but it's definitely possible to fingerprint a browser and track its requests to a server even if there aren't cookies. The level of confidence will be good enough for advertising.

Indeed. Which is why I like to use a separate browser for social media. Having said this I know it's a losing battle, but I see no reason to make it easy on the bastards.

(I've worked in ad tech in a previous life)

Re: Ask HN: How was this ad targeted to me?

#26

Post by mxvzr »

netsharc wrote: post #22
Bedon292 wrote: post #10

Facebook doesn't need to be open in a tab for it to know it was you on that site, and you don't even need to be signed in. You and your computers are connected, even if you think you are careful. If you have ever signed into FB from home, they know that machine / ip / whatever fingerprint is you. Even after you sign out, its still out. Even if you are in ingocnito mode, its still probably you. Then you sign in to FB…

> If you have ever signed into FB from home, they know that machine / ip / whatever fingerprint is you. Even after you sign out, its still out. Even if you signed out, they probably still have a cookie tracking who you are, and when your browser fetches that Like button, it will still send that cookie to the Facebook server. It'd be interesting on a shared computer where 2 people (e.g. a brother and sister) log in to…

> Even if you signed out, they probably still have a cookie tracking who you are

Indeed: https://www.nikcub.com/posts/logging-out-of-facebook-is-not-...

Re: Ask HN: How was this ad targeted to me?

#27

Post by libertine »

NKCSS wrote: post #3

It's called re-targeting. You can use javascript to put users into a segment and re-target that segement; it's really easy. If you use the biggest ad-exchange (AppNexus) you can be sure to reach just about anyone anywhere.

Exactly - if op wants to he can install Ghostery, visit the website he was on and check if they had FB Remarketing pixel.

Case closed.

Re: Ask HN: How was this ad targeted to me?

#28

Post by ramshanker »

Bedon292 wrote: post #10

Facebook doesn't need to be open in a tab for it to know it was you on that site, and you don't even need to be signed in. You and your computers are connected, even if you think you are careful. If you have ever signed into FB from home, they know that machine / ip / whatever fingerprint is you. Even after you sign out, its still out. Even if you are in ingocnito mode, its still probably you. Then you sign in to FB…

It has happened so many times that I searched something on Amazon, and next day onwards, I get advertisement for Amazon on Facebook application showing exactly same product. I just wonder, who is paying for that advertisement!

Re: Ask HN: How was this ad targeted to me?

#29

Post by jorgemf »

There are so many ways:

- you opened a web page with a facebook's like button and facebook analyzed your browse history. If you browse for something in google shopping you might want to buy it, so facebook added it to your interests and showed an ad later to you. (Probably this was the cause)

- google and facebook knows your location because you have a google/facebook app in your mobile. It is easy to know where you work and where do you live. Even without GPS, as they can use the wifi public IP to know your location (among other things)

- your browse makes a fingerprint unique to you, even if you are not logged into any platform or you don't have an account on them they know you are you. So they can collect data. If you later login into facebook/google they match the fingerprint with your user. They can also use several fingerprint, because you use several devices. I think this is called supercookies. There are companies that just do this.

- you have two different devices with two different accounts, but you have the phone number of the other in your contact list and sometimes you have both devices with you. Facebook/google will suppose you both share same interests and show ads that match one of your devices to the other.

- "do not track" is a suggestion, some people ignore it because they really want to track you.

- google and facebook probably use other ad networks to sever ads, so facebook probably asked google (or another ad network) for an ad for you. You probably shared your phone number / email in both facebook and google.

- if you want to be fancy, machine learning could also help to target ads for you, but I think the other ways are so easy to do and work so well that you don't need complex things to show ads, just track the user.

Re: Ask HN: How was this ad targeted to me?

#30

Post by ramshanker »

netsharc wrote: post #22
Bedon292 wrote: post #10

Facebook doesn't need to be open in a tab for it to know it was you on that site, and you don't even need to be signed in. You and your computers are connected, even if you think you are careful. If you have ever signed into FB from home, they know that machine / ip / whatever fingerprint is you. Even after you sign out, its still out. Even if you are in ingocnito mode, its still probably you. Then you sign in to FB…

> If you have ever signed into FB from home, they know that machine / ip / whatever fingerprint is you. Even after you sign out, its still out. Even if you signed out, they probably still have a cookie tracking who you are, and when your browser fetches that Like button, it will still send that cookie to the Facebook server. It'd be interesting on a shared computer where 2 people (e.g. a brother and sister) log in to…

2 people sharing same computer has amazing effects on those trackers. My YouTube recommendations used to be awesome to my interests till I was single, Now it's all polluted and mostly useless after I married. ;)
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