As I said above, Microsoft knows that Salesforce's model is the future – their Office Live and Silverlight products confirm this. They have no particular reason to want Salesforce, but they have a very big reason to keep it out of Google's hands. A combination of Salesforce's sales team and CRM software with Google's Office docs and Google Gears to make the whole suite work offline is a real competitive threat to Microsoft Exchange. If Exchange crumbles, Microsoft could lose its control of the Office space. And since the future of software is delivery through the browser, Vista becomes an afterthought. Google and Salesforce software will run just as well on Macs and linux machines. When the enterprise market sees that they can knock $500 or more off the cost of a computer by going linux and Google/Salesforce, many will walk away from Microsoft completely.