What actually happens when you let apps track your activity?

No, your phone isn't listening to you without your permission. The idea that it might be is a shockingly difficult myth to dispel, given the fact that the alternative would seem to be that your phone is reading your mind. How else can you explain the ads you're seeing for that thing you never looked up online but did mention offhand to your coworker?

In fact, mind-reading is closer to what's actually happening. Your phone might not be listening to your voice nonconsensually, but speech isn't the only way you communicate your thoughts and desires. Over many years, the tech industry has built a staggeringly sophisticated mechanism that captures those nonverbal signals and converts them into ungodly amounts of profit. How fast are you scrolling on this page as you read? To which Wi-Fi or cellular network are you connected while you read? Did you find this article from a Google search, or was it shared by a friend on social media? All of these signals build a much more robust profile of who you are and, more importantly, which products and services you're likely to be tempted by than any amount of secret recording ever could.

So, what's actually happening when you do allow apps to track your activity, and what can you do to thwart their efforts? It's a complex question, and the answer differs depending on which specific activity type we're talking about. Breaking down the different permissions apps request to track you and how you manage those permissions on your device can help to simplify the issue.

Vampires are famously incapable of entering a private space without invitation. Data-collecting apps are far less polite  — on the plus side, they drink your personal data rather than your blood, but on the other hand, they don't like to take no for an answer and are much less likely to look like Robert Pattinson. So, how do you tell Google and Meta, and other data-hungry companies, not to make themselves at home on your devices? The most effective (though far from only) solution is to block device-level tracking.

Every device you own, from your phone to your laptop, has some kind of unique identifier that data harvesters can tie to your advertising profile. This allows them to aggregate the data collected across multiple apps on your device. Both Android and iOS use identifiers to track ad performance and user behavior across a given device. The difference is that you're opted in by default on Android, whereas iOS uses Apple's App Tracking Transparency (ATT) framework under which apps must ask you before accessing that ID.

Most people are at least vaguely aware that their activity is being tracked, even if they can't name all of the various signals they're giving off. Most people also don't like being tracked in this manner, even if they cannot articulate the specific consequences. To substantiate that claim, look no further than Meta's admission in 2022 that it incurred a $10 billion loss after Apple implemented an ATT pop-up that gave iPhone owners the option to opt out of device activity tracking when an app is launched. Unsurprisingly, the vast majority of iPhone users chose to slap Mark Zuckerberg's hand away from their digital cookie jars.

On Android, you'll need to go to the Google section of your settings app, then tap on Ads and delete your advertising ID. The good news is you only have to do this once, as the ID will not be replaced without further action on your part. iOS will not actually allow you to delete the equivalent ID from your iPhone or iPad, but you can lock it down by going to the Privacy and Security section of the Settings app, tapping Tracking, and turning off the Allow Apps to Request to Track toggle, then turning off Personalized Ads from the Apple Advertising section of the Privacy and Security page.

While tracking permissions link activity to your specific device, sensor permissions provide data from your device's onboard sensors, such as the GPS, camera or microphone. These are thorny permissions. Plenty of apps need them for legitimate reasons, but that's no guarantee they aren't using the collected data in other ways. Google Maps won't be much use without access to your location, but Google is also using that data to "show you more relevant ads" per its policy documentation . And although Instagram needs camera access before you can use it to snap a photo for your Story, it is also scanning objects, faces and text in those photos to (take a wild guess) show you more targeted ads.