I think you got downvoted for asking a foolish question. If there were linux builds in the plans, they would have announced it. If open sourcing the whole thing was planned... well, you get the idea.
I don't see what is foolish about the question (and was taught [and believe] that there are no foolish questions).
MS has opened up their flagship development platform (.NET) and even has it building on Linux. MS will also rent you Linux virtual machines.
The post also talks about interoperability and running across many kinds of devices, including "try out RemoteIE which will stream our latest browser from the Azure cloud to Windows, iOS or Android devices."
First of all, the team who open-sourced .NET is a different one from that that is building IE. DevDiv has been very open-source-friendly for a few years by now.
Then there is the fact that .NET is far less tied to the platform than IE is. .NET is nothing more than a VM, runtime and GC. That's fairly easy to get cross-platform, compared to a GUI application that makes use of platform libraries for hw-accelerated drawing and text rendering.
Edit: Really? Downmods for a legitimate question?