Yeah, what is hooked up to your PC and what their IDs are. Because Microsoft really has to know.
Basically, if you travel with a Windows machine, Microsoft knows where you've been if only you touched the Internet, because of those personally identifying data points. You don't need a Microsoft account for them to know that.
If you change a video card or hook up your friends printer, Microsoft knows too. They even know which friend you likely took it from.