Microsoft says they need to do a better job about disclosing this, but the Genuine Advantage tool contacts Microsoft daily. It doesn’t do this to track your browsing or downloading habits, but to check and see if it’s ok that it’s still running. According to this article, they have some concern that it might not work properly and wanted to be able to tell it to shut down if there were widescale problems with the proof of legitimate windows copy. I did glean a few more details from the article that correct an assumption that I made a week ago.