Read about it yesterday and apparently it sends data back to Microsoft
By default, the virus scanner reports back to Microsoft with details of the machine, including the operating system (its product ID, among other things), installed drivers, and installed applications. Microsoft said that the collected data would be used to "help us improve scanner features and make better recommendations." The user can choose to not transmit some of this data by clearing a check box in the scanner window.
Edit: I just realized the article you posted and the one I did are different URLs, but it's the exact same story.. At least they did give the same author the credit
There are two rules for success in life:
Rule 1: Don't tell people everything you know.