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> and they combine the cookie ids. And how do they do that? The "advantage" of third-party tracking is that a cookie set by the analytics service on site A get
by icebraining 8y ago
> and they combine the cookie ids.
And how do they do that? The "advantage" of third-party tracking is that a cookie set by the analytics service on site A gets sent back when the user goes to site B and C and D (etc).
Without that, they have to somehow figure out that user 34 on site A is the same as user 95 on site B. That's often possible, but much less reliable.
- puffy_magicdrgn 8y agoI assumed the grandparent meant how do "you" track across your own properties.. For the likes of google and co, I wouldn't be surprised if we start seeing more ad companies requiring you to send some other PII via the api so they can turn a random tracking ID into an email address or whatever though. The same user on a.com and b.com get different ID's, but a.com and b.com both send data to tracker.com which maps that ID to an email address and then tracker.com can easily combine 'em. Not sure it's legal to do so, when I was working in this space we were quite forbidden from mixing up tracking information from various properties
- chkuendig 8y agoNo, I meant across different properties of different publishers. I assume that's still only possible with browser fingerprinting, IPs etc. So blocking third-party cookies is a good start to avoid tracking across different publishers (which is the big no-no for me, the fact that a single publisher knows what i read of his is not such a big issue and not that different to what has always been done by just crawling the ht_access logs...)
- cphoover 8y agoBrowser fingerprinting? How do you defeat that? If people want to track... they will track.
- londons_explore 8y agoSite B has an iframe back to site A and the 'user 34' cookie can still be read. All these protections only prevent setting cookies, not reading them again.
- icebraining 8y agoIt does prevent them from reading too: "Domains classified as trackers are not able to access or set cookies, local storage, and other site data when loaded in a third-party context." (emphasis mine) https://blog.mozilla.org/security/2018/10/23/firefox-63-lets-users-block-tracking-cookies/ https://blog.mozilla.org/security/2018/10/23/firefox-63-lets...