With the release of iOS 6.0 -- the operating system used in iPhones, iPads and iPod Touches -- Apple replaced its controversial Unique Device Identifier with Advertising Identifier, after it was discovered some developers were misusing information accrued with the former. Advertising Identifier limits but does not totally eliminate ad tracking on your device. Version iOS 6.1 gave users the ability to change their Advertising Identifier at will. Here's how.
1. Once you have iOS 6.1 installed on your device, go to Settings. Select General and then About. Scroll down and select Advertising.
2. Slide the Limit Ad Tracking toggle to the ON position. Although this advises advertisers you do not want to be tracked for targeted advertising, there is no enforcement to prevent them from accessing and using your advertising ID.
3. Finally, press Reset Advertising Identifier, and then Reset. This generates a new unique nonpersonal, nonpermanent Advertising Identifier for your device. Advertisers will now effectively see your device as a new one, making any information they may have previously stored about it useless.