If I didn't have a smartphone, I suppose it's theoretically possible the Windows 10 upgrade could be my greatest privacy/anonymity concern. That theory however depends on a a universe in which I never browsed the web with cookies enabled, never played Flash content that I wouldn't want to watch with my mother, and never typed anything into the Mountain View company's search box.
In this universe, I actually have less concern about Microsoft doing something creepy with my keystrokes than I do about Canonical doing so. I run Ubuntu and it wants to send my keystrokes to Amazon and whichever search engine has the current paid placement in Unity. At least with Microsoft it's not continuous direct monetization.
If Windows 10 was a big concern, I wouldn't install it or run it on any of my computers. But that's just me. I run Ubuntu for other reasons. The machines I've upgraded to Windows 10 have had most of the crap turned up except for the peer to peer upgrades. It's right there in the install.