Apple restricting third-party advertisers from collecting personal data if they are owned by another platform vendor could be a way of preventing Google's AdMob from competing directly on the iPhone with Apple's iAd, but it could also be a sign that Apple, cranky after leaked iPhone prototypes and iPad analytics, is determined to take back control of user data.

Steve Jobs was nothing if not heated at the D8 conference about the leaked iPhone prototype, and perhaps even more so about in-app analytics taking user data, including device and location, and using that to reveal details about the iPad long before it was announced. Imagining Apple's subsequent reaction to the thought of now-rival Google having early access to such detailed information not only about unreleased Apple devices, but about which devices iOS users have, at what location, and their app usage patterns probably sent a chill down their collective spines.

App Cubby's David Barnard put together an excellent post about it earlier today:

When you use Google search and other Google products, they collect a tremendous amount of information and use that information to customize and better serve the ads that are the core of their business. Many users don’t even realize this is happening, others are comfortable with it and have some level of trust for Google’s intent in using that data.

Well, Apple doesn’t trust the benevolence of Google, developers, and other third parties involved in the iOS platform. Apple wants to control the flow of user information.

Barnard also points out Apple primarily makes their money off hardware sales, not the brokering of user information the way Google or Facebook do. He also suggests part of AdMob's $700 value to Google was exactly the type of data they could pull off iOS devices:

[David Barnard / App Cubby]