C# from Microsoft runs on Windows. C# from Mono Project runs on Mac, Linux, etc.

>The interesting part - for me - is that about 2/3 of development is done for Windows; I thought the percentage, at least in the U.S., is much higher, perhaps closer to 90%.
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>This reinforces what I have been thinking a while ago, that, if I learn a new language, it should be something that runs on multiple platforms. (Something ONLY for Linux would not be appropriate, either.)
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>That might be Java - the company where I give classes for Cisco Academy also happens to teach the official Java course from Sun Microsystems. This same company also teaches the official MicroSoft courses, including .NET; but I do not consider this as convenient, since it seems to be more oriented towards Windows.
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>I know there is also a host of other multiplatform options, some of which were mentioned in the article. Languages such as Python, Perl, PHP, and others.