Microsoft had a really bullying culture back in the day -- when everyone was locked in, they seemed to really enjoy turning the screws. They were almost like villains from comic books or something.
But Windows was always comparatively open -- they have the most open of all the proprietary ecosystems. You can write you own programs and install them wihtout anyone's permission, you data lives on your disk, and anyone can write a device driver. It's more open than OS X (which only runs on Apple's hardware), and it's a lot more open than platforms like the iPhone/iPad, which only run programs Apple approves.
When Google released Buzz, it was a reminder that if they wanted to break gmail pretty badly, they'd be able to, and we'd have no recourse. With software on your own computer, you can at least refrain from running the upgrade.
It would be great if MS started pushing their openness as a selling point, and if they differentiated themselves from google in the cloud by being scrupulously responsible with our data. For example, I'd love to see MS roll out a privacy enhanced Bing -- no records kept, no targeted ads, for $10/month (or whatever).
Gmail won't even put marker tags in the Gmail HTML that would make it easier for FireGPG (a firefox plugin that supports GPG encrypted mail) to parse your mails, so FireGPG breaks all the time. They should do that instead of making empty threats to pull out of China.
The power concentrated in all of these companies is pretty troubling. Google at least has the sense not to be flamboyantly abusive with their power. Microsoft used to be almost theatrical in their bullying. That's dogging them now.