I recently discovered that our I devices have Advertiser tracking enabled by default within the iOS 6 Operating system, to the geeks this is basically identifierForAdvertising (IDFA) and identifierForVendor (IDFV), Apple had previously limited by denying app developers use of a device's UDID, but advertisers can now track and target users of the operating system.
To the non geeks this is basically tracking for Advertisers to target you to show adds that relate to your apps and what you search for on your phone.
To turn this off follow the procedure below.
Go into Settings > General > About.
Scroll down to Advertising.
You will see that Limit Ad Tracking is OFF by default, So what is the problem, if it is set to OFF you are open to the advertisers, simply slide it to ON and you will now be free from tracking.
You can click on the more info option at the bottom of the screen which basically tells you about what the Ad Tracking does, as per the image below.