The question has been asked again and again, and again. I've read so much about it; in fact, I've seen a coupla videos on You Tube that mock the similarities between the two operating system. In last weeks InfoConnect 2007, I've had people come up to me and ask that, with a 'gotcha' grin on their faces. Is Microsoft imitating OS X; or any other operating system?
To answer this question I refer back to a video I saw a few years ago, of Steve Ballmer, Microsoft's CEO talking to a gathering of over 30,000 Microsoft employees. In the video, Mr. Ballmer came hopping on to the stage and for the better part of 3 minutes, all he did was jump around and shout; developers, developers, developers, developers.
Yes, arguably, Microsoft may have borrowed :-) features from other operating systems, but the main difference here is the humongous support Microsoft provides to its developer community. After all, an operating system is ONLY as good as the number of applications running on it.
The .Net framework is debatably the most widely used development framework in the world; and it is ONLY 6 years old! It is very important to realize that Microsoft has never released a new product or technology before providing developer support earlier. Almost everything in every Microsoft technology is programmable.
As a matter of fact, you can download developer tools, from the Microsoft website, that will enable you to create applications for all versions of the .Net framework, for free. Plus, Microsoft provides every means of developer support thinkable. The documentation is extensive (a Microsoft tradition) and there are at least a gazillion forums online that will provide you with every bit of information you want.
Yes, at face value, both operating systems are similar, but that is the extent of the resemblance.