I can't believe I've been using Linux for over 15 years now. I simply can't believe it. Time has flown by so fast. If you had told me 14 years ago that I'd still be using Linux as my main desktop operating system, I would have assumed it was because something big had happened, and would have probably even gone so far as to say Linux must have grown into a force in that time.
Both are correct, but neither has anything to do with the desktop. Linux is big. I would even say Linux is now a force in the computing marketplace. Unfortunately, it's still only on the server side. Linux continues to grow some on the desktop, but my anecdotal evidence seems to say that it is really only growing significantly in embedded type desktops. I'm talking about corporate controlled environments where applications are limited and control is being kept in the IT department. Or on college campuses where Linux installs are available to integrate with the campus Unix environment. Or even on specialized products like Asus Eee PC, which was intended to be absolutely as cheap as possible yet still powerful enough to be an enjoyable machine to surf the web and do email (and it is, BTW, though I still can't believe Asus didn't put Bluetooth in it...wait, I already did a bluetooth rant today).
Linux will continue great success on the server side, and I believe this is mostly due to the open source model. Server applications are vertical in nature, and by that I mean you typically install one server to do one thing (ie. be a web server). Even when you have it do multiple things on the same server (ie. web, email, file sharing, etc), those things aren't generally highly connected. They also need the same general resource set...disk, RAM, and network. When you combine that with the open source model, you find you have so many people with exactly the same set of needs that invariably enough of them will have the skills to make those applications work so well that we find ourselves where we are today...Linux is a really good server platform.
You might think "well, if that's the case on the server side, just imagine how good it can be on the desktop since there are a lot more people using desktops than hacking on servers!" Wrong. I used to think that way, but have since come to realize this will never happen. Sure, Linux will achieve some success on the desktop, but the fact of the matter is that the Linux desktop community will always remain far too fragmented. There are too many people with too many divergent needs on the desktop. When you combine that with the fact that desktop applications need a LOT more in the way of resources (you need the same stuff a server needs plus things like high end graphics, many more input devices, layers of communications, etc) and you end up with a much larger matrix of things to support. Combine that with the ever changing PC hardware landscape, and you end up with an unsupportable nightmare of building blocks for an end application vendor.
Sure, some application vendors have done it. Sure, some application vendors never will and in many cases the open source world has stepped up with an amazing application of their own (we have very good office suites, email, web browsing, etc). But in far too many cases we see people with applications that they could likely never support on Linux. There remain far too many different distributions that it becomes impossible to even figure out which one(s) to target. The resources that an application need to rely on are constantly being improved, but that means constant change. That change scares many vendors because of the support issue.
Basically, to me, what it boils down to is that the best thing about open source, the ability to rapidly improve it, is the thing that will keep Linux on the fringe of desktop acceptance. I thought that about ten years ago but honestly thought things would eventually come together in many ways, become more stable, and allow Linux to see application vendors support it more. Over the last couple years I've come to realize that I may always need a Windows or Mac on my desk for some things (or at least an emulator running some other OS), and I am no longer confident there's an end to that in sight.
To the folks who continue to work on the Linux desktop, please take this as a challenge. I implore you.