Apple’s take on Do Not Track for iOS6:

“Ad Tracking: iOS 6 introduces the Advertising Identifier, a non-permanent, non-personal, device identifier, that advertising networks will use to give you more control over advertiser’s ability to use tracking methods. If you choose to limit ad tracking, advertising networks using the Advertising Identifier may no longer gather information to serve you targeted ads. In the future all advertising networks will be required to use the Advertising Identifier. However, until advertising networks transition to using the advertising Identifier you may still receive targeted ads from other networks.”

Cool.  If you can find it or even care!

Thanks to Steve Smith and Media Post 
MediaPost Publications Will iOS 6 Users Even Find The Limited Ad Tracking Toggle? 09/17/2012