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Comment by setra | Hacker News Reader

How are they targeting location at such a high resolution? IP targeting is usually only accurate at the whole city level. In this they show tracking across a bus path. That would require GPS. What am I missing?

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Ad networks allow advertisers to target based on fine-grained location which is presumably matched against the location reported by the phone's location services. That is, an app with GPS privileges displays a Geo targeted ad, then that display is reported to the advertiser. So yes, this is using GPS after a fashion.

So this has nothing to do with browsers or ISPs; it's a result of apps with GPS permissions transmitting that information to advertisers without the user's consent?

And/or users handing over consent for the app (and included ad-tech) to use GPS data without thinking through/caring enough about the consequences. Additionally, predatory apps that demand certain permissions to work can function to force the user to give up GPS data.

Maybe after the user declines a permission and the app prompts again, there should be a checkbox on the permissions prompt that makes Android pretend the permission was granted and just spoofs the relevant data.

That still means that you're safe if you don't use those apps. I just checked, none of the apps on my phone have location services always on, apps such as Facebook have it set to never. And I can't remember Facebook ever bothering me with it (as long as I don't post something at least).

This is explained in the article. Apps use high-precision geolocation when requesting location-targeted ads, and you can target ads to specific locations, so if you blanket an area in ads you can indirectly track movement through the grid.

> They then used that DSP to place a geographic grid of location-targeted ad buys around a three-mile square section

The game the target installed that is snitching GPS coordinates to an ad exchange near you.

How else did you think localized advertising works?

OpenRTB has supported GPS location since October 2012, proprietary exchanges longer than that.

> One test subject's commute across Seattle that the researchers tracked with ads in the app Talkatone. The dotted lines show the subject's real path, while the red dots show where the ads were delivered to the subject's phone to reveal his or her workplace, bus stop, home and local coffee shop. (The subject's actual home location has been somewhat obscured for privacy.)

It's not tracking across a bus path; that's their actual path. The red dots are the tracked locations.

Look at the red dots it places down. Two of the dots are within 1/8th of a mile. All of the dots are within 4 miles. 1/8th of a mile resolution is extreme and not IP level.

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