Regarding MS: Nokia owns Qt. I'm not sure how much of a threat that framework might pose, but if certain claims are not exaggerated, I'm afraid MS might be interested in storing that particular piece of programming on a very dark and dusty attic. And that's just one reason.

If we consider the acquisition for a more defensive reason, ok, I'm gonna give my thoughts room to play, so this might sound mighty paranoid:

The N900, while not fully open, is still the openmost mobile platform I have ever heard of. We've (as a community) OC'd it, we've modified it, we've bricked many times, we've added features that Nokia had no plans of. The phone improved WAY beyond its state upon launch.

Much of this stems from its openness; while not fully customisable due to binary blobs, its still very flexible. Now, here's the thing...

Not only did the N900 run a very customisable quasi-open source OS, as it introduce a few of its users to linux. And guess what... While very complex if one was to dig into its guts, the phone was still plain easy to use. One could very well take that experience and through it realise that linux isn't some arcane piece of software that takes a hedge wizard to tame and use.

As said, tin foil hat time, and I might be wrong or otherwise might have simply incorrectly evaluated a few points... But assume that Linux actually spreads due to its adoption by a handset company. Maybe it makes sense to actually try to take such company down, or otherwise simply buy it.

Also, Intel is mostly a hardware company: It's business model is/would/will be hardware-centric, I assume, so they probably don't care as much about controlling its software than as to spreading it as much as they can, along with their CPUs. It's the FOSS spread scenario all over again, which surely could drive MS to acquire Nokia for this fact alone.

Or so I would guess, wildly.