Final Silverlight 2.0 ships Tuesday

So how will this change the complexion of Web applications going forward, especially since so much of the RIA realm has been devoted to JavaScript? I asked Scott Guthrie.

"I think there are a couple of elements about it. One is, what language does the developer work with, and how does that change how they build the application? And the other is, what are the capabilities of what they can do with that language?" Guthrie responded. "In some ways, the biggest difference between what people are building with Silverlight 1 and what they're building with Silverlight 2 is less about the language in terms of changes, and more about, what features are built into Silverlight 2 that they can do stuff with?"

One such feature he listed is Deep Zoom, which enables a control to show a very-high-resolution image -- much higher than the control itself -- and zoom in very smoothly to show detail. That feature is exclusive to Silverlight 2. Another is adaptive streaming, in which a video is encoded at multiple bit rates, and the Silverlight client is capable of switching between encodings based on the dynamics of the network at the current time.

From the perspective of a programmer, Guthrie cited the current test of the Silverlight-endowed AOL Mail client, which uses some programming principles that are atypical for a Web application. For instance, that particular client is capable of threading, "which is something you can't do with either Flash or AJAX, to do background indexing of mailboxes, and be able to do offline storage of e-mail within the browser in a secure, safe way," he told us. "Having that type of networking features, threading, and data features, and then being able to use whatever language [developers] want to program against it, has enabled a mail client that's [more] unique and different than anything else out there.

"One of the things we are really trying to do with Visual Studio, and with Expression, is provide a tooling experience that feels very natural to developers, and hopefully in a lot of senses, feels very comfortable and familiar. For example, with our Visual Studio tooling support, we have many, many millions of professional developers that are used to Intellisense, to Visual Studio project support, used to a rich debugger, and so on. And oftentimes, for a lot of developers coming from a client development background, they're used to a model where you add controls onto a UI form and you handle events against them, and you code against them. From that perspective, Silverlight will feel pretty familiar. The fact that, within your Visual Studio where you might be doing C++, a Windows Forms app, or using ASP.NET, you now have another project type inside your toolbox that allows you to run code inside the browser, on the client cross-platform...ends up being pretty powerful.

"And the fact that you can reuse those same skills," Guthrie continued, "whether it's a language skill, a tooling skill, or a framework skill...you're still going to need to learn some new things, but hopefully, it's very approachable, and we expect to see a lot of .NET developers in particular start building Silverlight apps pretty aggressively."

5:40 pm EDT October 13, 2008 - Some of our readers were apparently concerned that our explanation of Silverlight being updated through WSUS was a bit "sensationalistic," so for a more ground-level explanation, here's a direct quote from Microsoft's Scott Guthrie:

"If you are an end user who has installed Silverlight, by default, we'll auto-upgrade you to the next release, the same way we do for security patches and things like that."

In the enterprise, however, Microsoft relies on its update service WSUS, as Guthrie explained further:

"WSUS...basically is a package deployment model that we use across Microsoft and for Windows, which allows an administrator to basically control exactly when and what software is deployed, and whenever a patch is deployed as well. What that means is, an administrator -- even with Silverlight 1 -- could in a one-click way deploy Silverlight across 20,000 desktops without the user having to do anything in order to participate. Silverlight 2 supports that as well, and if you deploy through WSUS, or if you're in an enterprise environment that's managed using standard Microsoft servicing capability, then we won't automatically update you; instead, we'll tell administrators that an update is available, and then they can control their preference when the update applies."