Google has a Microsoft-specific search page here – http://www.google.com/microsoft.html
I found it while searching on google – quite amusing :)

Frog29, Yeah that was discussed in the forum earlier in the year. I couldn't find the exact post though.

There are search pages related to Microsoft, Linux and Mac.

http://www.google.com/linux
http://www.google.com/mac.html
and the link you found:
http://www.google.com/microsoft.html

... and they're from 1999.

and http://www.google.com/ie

And also Firefox
http://www.google.com/firefox

See the full list here:
http://www.google.com/options/specialsearches.html

[Moved from "Google Search for Microsort?" – Tony]

http://www.google.com/microsoft.html

"Search Microsoft-related sites using Google:"

What is that?

[Moved from "Google Search for Microsort?" – Tony]

It's a pretty old page. See: http://www.google.com/options/specialsearches.html

"Google's special searches enable you to narrow your search to a specific topic."

(It doesn't say which Microsoft-related sites are being searched though.)

[Moved from "Google Search for Microsort?" – Tony]

Mentioned not that long ago:

[Threads now merged...]

I think I'll add it to my list of frequent topics:
*Gmail has more Spam
*GDrive coming soon
*OMFG Google Killer