Over the last few months since Satya Nadella took over as CEO of Microsoft, the company has becoming steadily more open and cross-platform.
First, there was Office 365 for iPad and Android, then Microsoft offered InTune, for device management across Windows, Windows Phone, iOS and Android.
Earlier in November 2014, Microsoft announced integration between Office 365 and DropBox.
Now Microsoft has released .Net to the open source community, a move that could establish .Net as a cross-platform tool on Windows, MacOS and Linux. At the same time, it is offering .Net Core common language runtime (CLR) for Windows, Mac and Linux.
There is also a free version of Visual Studio Professional for open-source developers. This is called Visual Studio Community.
The .Net Core stack, runtime and framework libraries will all be available through GitHub.