The phone in your pocket has a unique "Advertising ID" that lets advertising companies track your app activity. While you can't remove this ID, you can reset it to erase all your activity.

Advertising IDs are present on iPhones, iPads, Windows PCs, and Android devices. They work similarly to "cookies" in web browsers. Your activity is tracked, shared---and sometimes sold---and then used to deliver up ads that you're more likely to click.

You can't remove or disable the advertising ID entirely. The best that you can do is to "reset" the ID. This wipes the slate clean, and if you do it regularly, you won't build up a big log of information. You can also opt out of personalized ads.

First, swipe down from the top of the screen once or twice, and then tap the gear icon to open the Settings menu.

tap the gear icon

Scroll down and select the "Google" settings.

Select the "Google" settings.

Next, select "Ads."

Select "Ads."

Tap "Reset Advertising ID."

First, tap "Reset Advertising ID."

Select "OK" from the confirmation pop-up.

Select "OK" from the confirmation pop-up.

Toggle the switch on for "Opt Out of Ads Personalization."

Now toggle the switch on for "Opt Out of Ads Personalization."

Select "OK" from the confirmation pop-up.

Select "OK" from the confirmation pop-up.

That's all there is to it! Getting ads that are more likely to be relevant to your interests might not sound awful, but there are obvious privacy concerns involved. You've taken back a little bit of your privacy.