Google Tracked iPhones, Bypassing Apple Browser Privacy Settings

“To get around Safari’s default blocking, Google exploited a loophole in the browser’s privacy settings. While Safari does block most tracking, it makes an exception for websites with which a person interacts in some way — for instance, by filling out a form. So Google added coding to some of its ads that made Safari think that a person was submitting an invisible form to Google. Safari would then let Google install a cookie on the phone or computer.”