If you click on an ad for the new Ford Taurus on a website that uses Google to serve ads (and Google serves about 13% of all online ads), then go to your local Ford dealership to check out the car in-person, Google (and the dealership) will be able to connect the dots without you ever knowing it.
This is old news, but it was news to me. This is creepy shit.
More from this Digiday article from 2013:
Dan Auerbach, staff technologist at the Electronic Frontier Foundation, said that users might not realize they’ve opted in to constant location tracking when they opt in to “location services.”
“The disclosure mechanism for these apps are pretty weak,” he said. “I think there’s a gap between user expectations and what apps are really doing.”
It gets even better for Android users:
It is easiest for Google to conduct this passive location tracking on Android users, since Google has embedded location tracking into the software. Once Android users opt in to location services, Google starts collecting their location data as continuously as technologically possible. (Its ability to do so is dependent on cell tower or Wi-Fi signal strength.)
The only way out of this tracking for non-Android owners is to uninstall every location-aware Google app from your phone, including Google Maps and Waze:
But Google can also constantly track the location of iPhone users by way of Google apps for iOS […]
Google’s namesake iOS app—commonly referred to as Google mobile search—continues collecting a user’s location information when it runs in the background.
You can apparently opt out of this on a per-app basis. Not sure how to do that, what it’s called in the app settings menu, or how many people actually do this.
See also: More about Google on this blog.