Apple no longer allows app developers to use the UDID (unique device identifier) code to track devices and device behaviors. The UDIDs are permanent numbers that can be tied to a specific device and, ultimately, a person. The lack of anonymity in this system forced Apple to look for another way to give advertisers the information they need. Well, it found one.
BusinessInsider spoke to advertising executives in order to understand the inner workings of the new system, and this is what's going on.
iOS 6 now uses something called an IFA--or "identifier for advertisers." The IFA is an anonymous number assigned to devices and users at random. Thankfully, it is temporary and can even be blocked. As iOS device owners use their apps or surf the Web, those apps and Web pages serve ads. In order to do that, the app publisher or website owner scans the IFA and passes it to the ad server, which logs the device's behavior and serves an ad based on what that person is doing with his or her device. Creepy.
Keep in mind, the IFA does not give away your personal identification. It doesn't tie John Q. Public to a specific device and behavior pattern.
[ Consumer privacy: is it a joke? Advertisers' 'Do Not Track' Protests Fail Smell Test. ]
The key part of this system, reports BusinessInsider, is that the IFA can be tracked by the ad company all the way to something called "conversion." This typically means when an iOS users sees an ad, clicks the link for that ad, and downloads an app or other content associated with that ad.
This system is on and active by default. I confirmed this on my own iOS devices. Thankfully, it can be turned off. Here's how.
The ad tracking setting is found by following the Settings -> General -> About -> Advertising path. Under that setting, you'll see something called "Limit Ad Tracking." When you encounter it for the first time, the toggle is in the "off" position. This actually means that ad tracking is turned on. In other words, your behavior is being tracked if the Limit Ad Tracking feature is turned off. If you want to opt out of targeted advertising and stop advertisers from following your online moves, switch "Limit Ad Tracking" to the on position.
As mentioned, this system is anonymous doesn't identify anyone personally. Even so, if you care to opt out, follow the steps above and you can feel slightly better than you're sharing less info about yourself with advertisers.