
Ask HN: How did Facebook track me across device, ip, and browser? - throwaway_x2089
The other day, I opened up incognito on my iphone connected to LTE, searched for a company on google, clicked on the first link. I then go to my laptop connected to a wifi network, refresh my FB newsfeed and see an ad for that company on my newsfeed.<p>Just to be 100% sure, I did it again with another company, refresh newsfeed, and see an ad for that company almost immediately.<p>How is Facebook tracking me? My thought process goes like this:<p>- can&#x27;t tracking by IP because the devices were on different networks<p>- can&#x27;t be cookies (or super cookies) because different devices (also incognito)<p>- unlikely based on location because not precise enough with LTE<p>which leaves:<p>1) browser fingerprinting on my mobile phone linking me to an identity and that data is fed into Facebook in real-time?<p>2) My cellular provider is funneling data to Facebook?<p>Am I missing something?
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qbrass
They track your location by scanning for nearby wifi APs that they know the
locations of.

