An interesting article about the challenges that would be faced merging applications and infrastructure were the Microsoft/Yahoo merger to go ahead.
Some interesting quotes that indicate just how much Microsoft considers itself to be a walled-garden;
Microsoft’s data centers run on proprietary software that is incompatible with the open-source programs and applications adopted by Yahoo.
A small music start-up acquired by Microsoft in 2000. At that time programmers spent the better part of a year rewriting its technology infrastructure to make it compatible with that of Microsoft
When Microsoft tried to absorb the Hotmail electronic mail service it acquired in 1997 it spent over 3 1/2 years moving it from it’s open source technology platform to Windows own one
If we add the technological challenges to the corporate culture ones, we can see why over at the Googleplex they must be shaking in mirth and the prospect of the merger going through