Just as an example: http://jeffhuang.com/best_paper_awards.html
(Scroll to the bottom, and see that MS is #1, ahead of e.g. MIT, which is #3 on the list, and far ahead of Google which is #17 on the list)
From the outside imo it feels like it took ages for them to start this change, but actually doing it once they first started open-sourcing things seems to have been an incredibly quick switch, over just a couple of years. Has there been loads of progress on this in the background that's just only become visible now?
"How I can notice this change of strategy?" may you ask, It's because they always said things like this, per example, that Linux was not good because something open source could never be better than a closed and proprietary system with a company protecting their code.