Apple decides to track its customers
Apple is well known for their approach to "own" their customers instead of just selling stuff to them. Enforcing restrictions such as forcing its customer's to buy Apps off Itunes have had a negative impact on the company's image.
Now though Apple has announced it will track each and every Apple Customer and use that information for their own use as well as distribute it to other companies that develop applications for Itunes. Although you can avoid sending information to third-party companies, you can't stop Apple using that same information otherwise they will restrict access to the Itunes Store.
According to Apple, there is "no harm" in letting Apple follow you around since the information will be used to provide essential data for apps such as MobileMe.