Windows introduced SmartScreen back in IE8, which scans for known or possible malware linked URLs, even before clicking on them. Additionally, that would check files before / during download. What that did is have to send the info to a database at MS to compare against.
They expanded this to the applications in Windows 8. What that means is that at least your basic hardware information and application info (meaning name, build, etc.) are sent in as well. They build a "trusted software database" off of this.
Could they link your usage and who runs what using this information (along with your IP that they get upon connection? Absolutely. Is that the intention, I doubt it (but there are always those that think MS is evil who would disagree.
Here is a good article from The Verge.
2Windows 8 does not require a Live ID. The Live ID is only useful for cloud storage & migration of application setting, office 2013 documents, etc. You can create local user accounts just as you always have if you are that paranoid. – BBlake – 2012-11-28T20:07:48.190
2Microsoft does not monitor your activity. – Ramhound – 2012-11-28T20:44:26.507