One of the less immediately apparent parts of the iOS 4 update is the addition of the iAds system, which is launching in July. While it can’t be shut off, users can choose to have it targeting them personally or not.

“Apple and its partners use cookies and other technologies in mobile advertising services to control the number of times you see a given ad, deliver ads that relate to your interests, and measure the effectiveness of ad campaigns,” notes Apple. “If you do not want to receive ads with this level of relevance on your mobile device, you can opt out by accessing the following link on your iOS 4 mobile device: http://oo.apple.com. The message ‘You have successfully opted out’ will appear and you will be automatically opted out of interest-based ads.”

“Make sure you are using a mobile device running iOS 4 or later,” Apple adds. “If you receive an ‘Opt out not successful’ message, please wait a few hours and try again.”

Source: Support.Apple.com