[chousuke]

I work for a hosting provider. Windows exists and it's used for corporate infrastructure, but the vast majority of actual applications and support services are running on Red Hat, CentOS or Ubuntu.

Windows trends to be reserved for AD, jump hosts (much to my chagrin, I prefer SSH), virtual desktops and stuff that end-users access, because user management is where Windows is still ahead.

I suppose in small businesses they will have all the user management bits but no need for more than one or two "real" servers, so it doesn't matter if it's Windows too.

In bulk, Linux servers are much easier to manage though and since most application platforms will work just fine if not better on Linux, it's just the sensible choice unless you have something specific that requires Windows. Generally easier licensing certainly does not hurt.

The fact that on any Linux distribution you get trivial, easily-managed access to thousands of software packages free of licensing worries out-of-the-box makes for a large advantage over Windows where the concept of using a package manager and central repository seems to be a fairly new thing and you have to set everything up yourself or just deal with developers and users installing random crap from who knows where because by default there's no better option. There's also the fact that Linux server software tends not to have GUIs because servers are headless by default, which also makes them easier to manage once you run out of fingers to count them.