

Ask HN: How is this 'cross advert' possible? - bikamonki

I was logged into FB on one tab and then searched for a bike on Amazon, on a new tab. I <i>think</i> that I was not logged into Amazon. A couple of hours later I logged back into FB and there was this ad: http:&#x2F;&#x2F;www.grupster.com&#x2F;crossadvert&#x2F;fb_ss_blrd.png.<p>How do they make this work? Cookies? Do I have adware on my laptop&#x2F;browser? Do FB and Amazon share traffic data? All of the above?
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thisiszen
[http://www.perfectaudience.com/](http://www.perfectaudience.com/)

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bikamonki
Thanks, this explains it! Annoying and scary....

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greenyoda
It's also possible that it was a coincidence.

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bikamonki
If it was the first time, maybe. I've seen it also when browsing my local
newspaper site: ads with sites/products I use/search for.

