I think Silverlight represents the likely future of computing for most of us. And by “us”, I mean both Windows and web developers on the Microsoft platform (and maybe beyond).
I think we’re at a point of convergence, where two industry trends are coming together in a way that makes Silverlight the most compelling answer for a lot of development scenarios. These trends are the continued abstraction away from the hardware, and now the operating system; and the likelihood that the web as we know it is nearing the end of its life, so we’re looking for the next big thing in that space.
Part of the appeal of Silverlight, and the reason it almost instantly gains traction in any conversation with my clients, is that it is independent of Windows. They like the idea that it works across Windows versions without worrying that Microsoft will fix some Windows thing and break their app.
Some of them, especially those that deal with the government, really like that it works on the Mac as well as Windows. They have cross-platform requirements mandated by either the market or by law, and Silverlight gives them the option of using .NET (which they love) to run apps on the Mac.
Another part of the appeal of Silverlight, across the board from what I can see, is that people don't trust ClickOnce. But they do trust the browser as a deployment vehicle. I suspect this goes back, somewhat, to Silverlight being independent of Windows, while ClickOnce is more vulnerable to the OS itself. Our overall experience with ClickOnce is that it works great 99% of the time. And then 1% of the time it fails for no reason anyone can figure out. Same target machines, same configuration, but it just doesn't quite work. Maybe, over time, we'll find out Silverlight is also unreliable in this manner - but early indications are that this is not the case.
If you look at the theme here, it is about escaping the OS and all its complexity. And that's not entirely surprising.
We build the first OSes to abstract the hardware. And they evolved over decades until they were terribly complex, and somewhat intertwined with the hardware (driver issues are the major failure point for Windows).
So we built runtimes to abstract the OS (starting perhaps with Smalltalk, then VB, the JDK and now .NET). And they evolved over the past couple decades until they are becoming terribly complex, and somewhat intertwined with the OS (installing/upgrading .NET usually requires a reboot of Windows).
It appears to me that we're now building smaller, decoupled runtimes that are a bit less complex, and that are intentionally decoupled from the OS, and are largely self-contained. It is just the next step in the evolution - though I suspect it does mean Windows (or any other OS) becomes substantially less relevant to most people.
By itself, I'm not sure that a runtime that is less coupled to the OS would be enough to drive Silverlight’s future. But there's another dynamic here too: the aging of the web, and the search for "what's next".
I was subscribed to the Usenet newsgroups in the early 90's, when they were discussing the future of the global network. When WAIS, Gopher and HTTP were competing (Gopher came from Minnesota after all : ) ). And HTTP/HTML won, because they really were the superior document viewing technology. A global version of lex; something that should have filled the role of PDF.
But as we got into the mid-90's, people started bastardizing and hacking this technology. Warping it into something far different from its original intent. And that's OK - but it is important to realize this was done ad-hoc, with little or no pre-planning or thought of proper architecture.
I know, I sound like a CS purist, but really the web, as we know it, is a stack of horrible hacks, all leaned up against each other like the world's biggest and most expensive house of cards. In short, the technology of the web is a mess. Just witness the insanity around browser versions, the standards compliance farce, and the ridiculously inefficient ways we waste time/money building a web app that runs on more than one version of even one browser.
Yes, the web has transformed the world. And it revealed some very good patterns for software and usability. But it became mainstream over 10 years ago, and most technologies fade gracefully away at the 10 year mark. So it is time for the web (as we know it) to die.
The question then, is what comes next? Do browsers become the new standards-based OS? Or do we extend the runtime concept into the web, as a long-term replacement.
Google is betting on the former, with Gears and Chrome. They clearly hope/expect that the browser itself will be the next OS - the thing that makes Windows and Mac OSes irrelevant. Adobe is betting on the latter. They clearly hope Flash/Flex/Air will be the runtime that makes both the browser and the OS irrelevant.
Microsoft is playing a smart game, imo. Silverlight (with Mesh and Azure) represents a strategy very similar to Adobe's (but bigger), where a runtime may well make the browser and the Windows/Mac/Linux desktop irrelevant. At the same time, they've got WPF as a fall-back in case the core OS does remain important to the average consumer.
So I think these two dynamics - the desire by our customers to escape the shackles of the OS (not just Windows - the OS in general), coupled with the fact that the industry is looking for the next step in the evolution of the web itself - work together to make this the perfect time for Silverlight to be the hot technology.
And I do think this works against WPF, because it neither helps us escape the OS, nor does it represent the future of the web. And it works against Adobe, because their vision isn’t big enough, nor their established developer base large enough. And against Google, because they are still trying to shape the stack of hacks that is the browser into something reliable, and I suspect that’s simply unrealistic.
In short, I think Silverlight offers the power needed for smart client business apps, with the best deployment and navigation characteristics of the web. Sure, it needs to continue to grow and evolve (the search issue needs addressing for example), but I really think Silverlight represents the future of development for most of us.