> If I showed up at your place and painted some tactful ads on the walls, would you have an issue with it?

Yes, because I didn't call you to paint anything on my walls. But if I hired you to paint me something on my wall every month, and gave you total freedom, then no, I wouldn't mind an occasional tactful ad. In fact, I know some people who buy (or steal) ad posters they find beautiful and put them on their wall.

> Or, if you bought a mattress and discovered that it hums some well-targeted, inoffensive jingle at 11pm every night, would that be fine?

No, I don't want my mattress to hum, mattresses are not supposed to hum. But if I bought a picture frame and that picture frame came preloaded with a tasteful ad, then I would be fine, because picture frames are supposed to have pictures in it. I can always change it later.

That's what I wanted to point out. That ad is a picture that goes where pictures should go, and blends in. It is not like an ad banner that goes where content should be, a billboard that block my view of the landscape, or that humming that definitely shouldn't come out of a mattress.

> But you paid for that OS

That component, Bing Wallpaper is free, I think. And I believe you can have it on other OSes. Bundling ad-supported software and services in paid software is still a dubious practice, but in this particular case, I don't think it is that bad, as in, pretty much everything else is worse in Windows.