It would be interesting to see how MS's kernel differs between client OS's and their servers. They have huge user camps both on the desktop and in enterprises,

It would be interesting to see how MS's kernel differs between client OS's and their servers. They have huge user camps both on the desktop and in enterprises, both of which are major, strategically important profit centers. The GPL pretty much ensure a server centric development model on Linux, though. Most open source developers and supporters aren't quite so 'open' with their own companies' source code, thus preferring to 'distribute' their apps as web apps, requiring no source disclosure.