http://www.google.com/search?hl=en&q=.com&meta=

#1. Microsoft
#2. Yahoo
#3. Amazon

Where is Google?

Google.com shows as #11 here. I think it might indicate that "go to Microsoft and do this and that" is less popular phrasing than when you say e.g. "go to Google and search for bla". So people might use the words "go to Microsoft.com and do this and that" and hence increase the "com" factor for MS.