The Financial Times:

Google is phasing out the internal use of Microsoft’s ubiquitous Windows operating system because of security concerns, according to several Google employees.

Bound to happen, the question is not who will follow suit but when, and how long it will take Microsoft to respond. I don’t think companies should or will abandon en-masse but I do suspect that companies, like Google, that have built out around multiple platforms will do so with great ease. Microsoft you should have Ballmer and Schmidt in the same room to fix this before you really start to lose.