.NET going to Linux and Opensource

Server based only.  But its interesting to see the powerhouse of Microsoft open up all its development code to opensource and to Linux.  I wonder what the real reasoning behind the  release is.  Perhaps MS is feeling the heat of other platforms that are opensource and/or run on Linux?

http://techcrunch.com/2014/11/12/microsoft-takes-net-open-source-and-cross-platform/?ncid=rss&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Techcrunch+%28TechCrunch%29