Apple has rather sneakily enabled Ad tracking by default in iOS 6. Like many, you probably weren’t even aware of it.
However, the good news is there is a way to limit this by simply enabling a toggle (rather counter-intuitive no?)
How to Limit Ad Tracking in iOS 6
The toggle is located in Settings > General > About > Advertising (not “Settings > Privacy” where one would assume it would be).
Set “Limit Ad Tracking” to “ON“.
The following screen shot summarises this.
And there you have it, less invasion of privacy, and it should technically save you some battery life. What this actually does is limit the information that apps send to advertising networks for the purposes of delivering more ‘relevant’ or ‘targeted’ ads across apps.