Todd Hoff's High Scalability [1] is a very nice blog to follow if you like this kind of information about real-world stacks. He's been writing it for years. (Caveat: It's a while since I followed it closely.)

[1] http://highscalability.com/

Stuff the Internet Says on Scalability is an excellent weekly article he does with plenty of great resources. Lots of stuff that's just reposted from HN, but also many pieces on real-world architectures that I never see on HN or /r/programming.

Not at this level of detail, but in the event you don't know about the site, try http://stackshare.io/stacks . You can see the app stack for the included companies at the levels: Application & Data, Utilities, DevOps, Business Tools.

Most of the places that have highly scaled Windows infrastructure and highly fault tolerant architecture tend to be the kinds of places with very paranoid middle managers..

Source: I work at one.

Match.com and PoF come to mind -- Match on the very large infrastructure side, PoF more along the lines of "punching above its weight."

There tons of big .net stacks, you just don't here about them in the startup world.

In the corporate world however....