Which begs the question of course, why? What's the purpose. Well, Microsoft has all kinds of happy clappy PR about how it's going to make all kinds of rich content available, blah, yadda.
But we have that today, with Flash and others. But Flash is not a Microsoft tech, so we all knew that at some point, it was going to be a problem for Microsoft. Hence Silverlight. Now, that's not to say that Silverlight doesn't have its advantages, but it has some serious disadvantages too. First and foremost, it's a cross-platform product from the Windows side of the Microsoft house. Over the years, I've learned that any cross-platform work from that group either has a lifespan measured in a single major version, if that long, (Cross - platform Active X, Outlook 2001), will be introduced in a fanfare, then upgraded rarely, if at all, never really work right, and in general be a total pain in the ass, (Windows Media Player, Services for Macintosh), or exist only to try and get people to dump !Windows for Windows, (Services for Unix). Sometimes, Microsoft doesn't really do a damned thing other than PR, (The Sun deal, Port25), and they can't even do that right, (The Linux vendor deals while making vague threats of IP suits against Linux users).
In other words, once you get outside of the Mac BU, Microsoft's cross - platform efforts lack trustability. Honestly, I'm not taking it seriously until the release of Silverlight 2.0 for !Windows with 100% feature parity with the Windows version.
Secondly, the dev tools are all Windows only. Oh sure, you can write XAML in a text editor, but then again, in theory, you can code Word with a text editor. Yet no one seems to do that. The issue here is that to do "real" Silverlight work, your coders, your designers, pretty much everyone involved with Silverlight from a creation standpoint has to move to Windows. Now, let's see...move a lot of Mac and Linux content creators to Silverlight due to great promises and PR from Microsoft, and a couple years later..."Oh, we're moving it to Windows only, and redoing the licenses so you can't use it anywhere else." Oops. Oh, yeah, it's happened before. Remember Rotor? Rotor version one was cross platform. Version 2? Windows only. Surprise!
So right now, Microsoft's sole real-world commitment to Silverlight, as in, they spent money and created code, the only commitment I take seriously from any company, is a web browser plugin for Mac OS X. Novell and others are handling Linux. So the Linux people get an artificial delta anyway. Yay for them.
But why? It's not just to push .NET, Microsoft could have done that years ago by fully backing Mono. What does Silverlight do?
Well, first, it makes sure that Microsoft has better controls over the dev environments. That's a big one. If they can get the major content providers over to Windows, then pull the plug on the non-Windows plugins, it will be at least a year, maybe two for anyone who went down that path to get back to being able to do cross - platform code. (If you don't think Microsoft would force you to only use the newest plugins, you have no clue about the history of that company.)
Secondly, and more importantly I think, it preserves and spreads Windows Media DRM, and it does so in a way that really sandboxes the content. What's the biggest complaint people have with Windows Media DRM these days? Well, if you're not running a Microsoft OS, you're kinda fuxx0r3d if you want to use it. But Silverlight makes that all go away. Now, you can provide Windows Media content with all the DRM you like, and best of all, it's locked to the browser. You can't save it to your hard drive! Well, not easily. The entire executive staff of NBC/Universal just came in their pants. Not only does Silverlight force a subscription model, but best of all, it's a more restrictive model with per - use approval. You could easily charge for every viewing of content with Silverlight, and the only way to get around that is to try and copy the video / audio stream to a local file. That's a lot of fun. Wait, no, it isn't.
Silverlight is the best thing to happen to DRM in years, which makes it the best thing to happen to Windows Media in years.
The sad thing is, while Microsoft and others try to push DRM, even with Silverlight, the rest of the world is realizing that DRM just doesn't work worth a crap, never will, and is figuring out better ways to deal with it that don't screw over the consumers. It's the last gasp of a dying model. If Microsoft really wants to make Windows Media universal, just open it up more. You can make tons of money with it, even when you aren't fucking over your users.
But Microsoft is incapable of being radical or even coming up with a new idea anymore, so they go down the IBM path, but they're still following IBM in the pre-Gerstner years. (No, The Man Who Invented Notes is not going to make it all better, get over it.)
They should have just called it "Blackout", because that's far closer to what it is really for.