It's been a couple of years since Microsoft stopped developing their Xenix UNIX system and sold it to SCO so they could concentrate on OS/2 and DOS. It's been some years less since Microsoft started providing Unix command-line tools for their professional Windows series which has lately come to a halt too.
After all, there's not that much ground-breaking "news" in this story.
About the technical part:
1. I wish they wouldn't distribute it in cooperation with Canonical, a company with a reputation that is rapidly decreasing for very good reasons. 2. I, for one, would surely have preferred the `ksh` which came with earlier "Unix for Windows" packages, IIRC it was the "MKS ksh", but I guess they had a reason. 3. I'm afraid of what this means for the PowerShell.