[cabalamat]

> How is OS X Open Source?

It isn't, but a lot of people develop on open source environments running on OS X. E.g. Python/Django. Because OS X is a Unix, moving between it and Linux for web development is easy.

> Azure runs Linux and other open source products quite well

This may be the case, but there is the perception (possibly an unfounded one; I've never used Azure) that Linux will always be a second-class citizen on Azure.

[digi_owl]

Not easy enough apparently, as there seems to be a concerted effort to clone OSX on top of Linux these days...