There is a really really obvious reason Microsoft gave away Windows 10 for free. They take 30% of all apps sales.
Give me a break. Solitaire is still free and *ad-free*. That's right I said Ad-Free, because it is if anyone actually bothered to open Solitaire on Windows 8 or Windows 10. If you want to play Windows XP, Windows 2000, Windows 98, Windows 7 solitaire aka Klondike solitaire it's still free and it's still completley ad free.
They also added, in spite of everybody here being entitled little brats, 5 other versions of solitaire like Spider solitaire and freecell. If however you want to try out one of the "Daily Challenges" you may use the curated, daily content for the outrageous price of watching an ad.
God, Slashdot has really hit a new low. God forbid an app, that can be uninstalled is included with a free OS that gives you 5 games for free but offers one tiny bit of premium content in exchange for an ad.
If your tin foil hat paranoid brain can avoid clicking on the daily-challenge button you get multiple high quality card game apps for nothing. Or you can right click on the app in your app list (because it's not even pinned to your start menu by default) and click "Uninstall". Lord have mercy! The pain and trouble! Oh my!
They aren't tracking your surfing habits more than google. They're tracking them exactly the same. The OS isn't scanning the contents of your files and applications and uploading them. Put simply this is some of the most rediculous FUD I've seen in nearly all of Slashdot's anti-Microsoft FUD. Which is saying a lot.
For fuck's sake, Solitaire is not part of some master scheme to spy on you. In fact of all of the large tech companies Microsoft is the one most actively avoiding ads to pay for their products and instead choosing for subscriptions.