To those who are skeptical of Microsoft's actions here, bear this in mind:
1. The old folk who ran the business before (Steve Ballmer, Bill Gates, et al) are no longer active there; they have been replaced by new people.
2. As proven by Windows 10, they are trying to listen, even if it means they aren't quite getting it right. I am (somewhat) hopeful they are getting there eventually; even if not with Windows, but with other business ventures.
3. Yes, it may just be a PR move.
To that I add:
1. New bosses, visibly new politics. They may be a little more open-source friendlier after all.
2. Well admittedly after trying Win10 I'm not impressed; that aside, they found people didn't like the new whiz-bang tile-only interface of Windows 1.0... I mean Windows 8. They are working on SSH in PowerShell. Clearly whatever new politics are present may be working well.
3. And so what if it is a PR move, or they're trying to sell Windows, or whatever? A bit of advertising surely doesn't hurt, if it means others benefit.
And a fourth point: A donation is *not* a contract, and as far as I am aware (correct me if I am wrong), the OpenBSD foundation does not govern OpenBSD development choices, and are (at least partially) separate entities to OpenBSD. So even if the OpenBSD foundation were to be corrupted by some super rich org, then given the separation between the two, with financial backing being the main link, and Theo de Raadt (an individual who has the calibre of, well... Theo de Raadt) running OpenBSD, an attempt at corrupting OpenBSD development like that would fail miserably, in Streisand-effect proportions.
Many are ranting and raving on the shady business of Microsoft, and yet ignoring the current and damaging shady business of Facebook, Google, and others.
Whilst I am not attempting to dismiss their past as insignificant, it is important to approach this with an open mind, and bear in mind that, given the other shady big corps around, Microsoft really ought to be the least of everyone's worries.