> Looks like MS thinks it's a "tip" rather than an ad.

No, they don't.

> edit: I think it's an ad too. Everyone would think so, except for MS.

You think a company with a $2.65 trillion market cap and an army of marketing professionals doesn't realize that what they're doing here is an ad, and didn't implement it intentionally as such?

That's not even remotely plausible. In the quantum multiverse which contains all physically realizable possibilities, that isn't one of them.