On February 5th GSK presented their 2008 year end results.
The presentation contains a very interesting statement about their migration from their current collaboration platform (I believe this is Lotus Notes Domino) to Microsoft Online Services.
On slide 43 they state :
Innovative partnership with Microsoft Online: 30% decrease in collaborative tool costs …
This illustrates quite clearly how Microsoft Online Services can contribute to substantial cost saving / cost predictability for organisations …
Source : GSK 2008 Year End Presentation