Heather Leonard in Business Insider:
Apple is leveraging iTunes user data to target iAds, which will make ads more user specific and targeted. By offering advertisers that targeting ability, they get more value for their ad dollars on the iPhone platform. Something that might not be as effective on Android, Blackberry or Windows 7. Google doesn’t have as much control over user data. Apple is set up to out-target Google in the mobile space.
Now we know why Google gives away the Android smart phone OS for free. Apple needs the competition.