<being_facetious>
Quick:
Name 2 Microsoft programs (not dev tools) that use MFC. Did you say Paint and Wordpad?
Great, name another....I'm waiting...nope...Scribble doesn't count!

Quick:
Name a shipping Microsoft application built on the .Net framework....that isn't a 'sample' application.
</being_facetious>

In all seriousness, I have heard a friend or two mention that Microsoft uses completely different libraries (and sometimes private/secret API's) for app development and the rest of us get the stuff that ships with Visual Studio.

The anecdotal evidence seems to support this at least to some degree as I just don't see a lot of production MS apps based on MFC or .Net. Is this just a misconception? Does Microsoft have a 'secret' set of libraries they use internally for all the cool docking toolbars and fancy windows we see in MS products? Am I asking too many questions?

Does a Microsoft developer sit down and use VS.NET all day like I do? Using the shipping .Net framework classes, or the shipping MFC? Or do they have 'special' development environments not suitable for the public?