[detaro]

There is an image CDN (EDIT: imgix, as tristanj linked below) which runs OS X for their image processing servers and I've seen pictures of rack holders for Mac Minis for build servers, but in general OS X isn't a very interesting choice.

Running it on non-Apple hardware is legally questionable at best (the EULA forbids it, if this part of the EULA is applicable in your country is a question for a lawyer), Apple doesn't do server hardware anymore, it costs money and you don't get support or special software from Apple for server-usage for it, and since nearly nobody runs it as a server OS it probably isn't very high on the priority list to support that usage for other software vendors or open-source project.

A lot of things probably will work well since they are made to run for developer usage, but if you do not absolutely need integration with something apple-specific or just want to reuse an old mac lying around for a hobby project it doesn't give you anything over other OSes as a normal web server.

[netik]

You're correct in that Apple doesn't manufacture server hardware like the Xserve anymore, but OS X, Server edition is still available and it will manage Apache for you (albeit in a terrible way, I don't like the excessive configuration they apply)

Many of Apple's own web sites run Apple hardware for outward facing, large scale serving (I used to work there).

At the end of the day, Unix is Unix.

I run nginx on OS X on a number of Mac Minis without issue and long uptimes.

[ksec]

>Many of Apple's own web sites run Apple hardware for outward facing, large scale serving (I used to work there).

Does that mean Mac Mini? Or Custom Hardware like Xserve.

[netik]

Oh, back then it was a wall full of XServes. These days, if they run Macs, they're probably racking Mac Pros.