In the news is a newly discovered Windows tracker that has some scary implications. It can be used to track your activities all over the Internet and was recently used against a Cyber-criminal case by the US Government. It involved information supplied by Microsoft and it reveals a level of tracking that we have not known about and works even if you don't use a Microsoft account. Just using Windows is enough to enable this tracking.
My Comments: Sounds like it uses the TPM chip to create this identifier. This is why I do not recommend using the security hardware as a part of PC hardware.