OSNews

"When thinking about web servers it is significant to think about what the servers will be serving. There are static text files and images - no server platform will win large market based solely on the ability to serve static files. This is not a selling point. That leaves us with other key technologies, most notably: ASP.NET, JSP and PHP. "

You forgot one of the most important -- Zope.

"Due to the inability for Apple to provide a version of its Mac OS System to other PowerPC OEMS it is unlikely that Apple will increase its market share in the hosting market. This would be the prime time for Apple to release an OS that is compatible with Mac OS X but not as "great", therefore leaving apple as the crown jewel of computer systems."

Er, isn't that really the niche that Darwin fills? For the most part Darwin is just Mac OS X minus the Aqua interface and iApps, which really don't matter much for a web server anyway.

As security is recognized as being more of a priority, I would expect that there would especially be gains in the Solaris, BSD, and Mac OS X area. HP-UX isn't bad security wise but they've been working so hard at alienating their customers over the years I don't expect them to reap any such benefits.

There's also the price situation. MS-Windows (under current licensing schemes) tends to be more expensive than pretty much anything else when you actually price the whole thing with reasonable hardware, in spite of its ill-deserved reputation to the contrary. Solaris, the BSDs, and Linux can run on anything that MS-Windows can (and more in fact) and give a lot more flexibility with hardware; Mac OS X is somewhat restrictive with hardware (although Darwin can run on pretty much anything that MS-Windows can, too) but the price/performance of an XServe beats out equivalent MS-Windows boxes for any realistic use once licensing is factored in. In terms of maintenance, the BSDs and especially Linux require a bit more expertise than the others and Mac OS X possibly a bit less.