Apple from day one let the cat in by placing Google maps and Youtube as default installed apps. Google is following up with great apps of its own service. But sometimes it conflicts with Apple's own interest and their relation with mobile operators (eg: Google voice).
Now the war is moving to a new field with the acquisition of AdMob. Advertising. By owning iPhone advertising, Google, who's behind the best OS challenging the iPhone, is a tough trojan in the iPhone. They have a massive power, since they own the second most important revenue chain that feed the app developers, after Paid apps (owned by Apple). They also own key estates and very soon data intelligence about apps that will place them at the level of second brain on the iPhone ecosystem after Apple. They can also, although i doubt the do-no-evil company moves that way, push iPhone users to their own apps, or why not to other android-powered devices.
I really wonder how Apple feels about that. Advertising on the iPhone is going to become big. very big. They can't really do a thing about that, except abusing their position and blocking any app using admob codes. But that won't happen, users and the FCC look to close
What could be their next move knowing that Apple is a non-advertising-based company?
ps: Maybe they should not so worry at the end of the day, when you see the kind of advertising AdMob served me..(see above)


