As someone who works a lot on Silverlight and as someone who have presented lots of trainings / talks over Silverlight; i am been getting a lot of questions based on future of Silverlight.
Is Silverlight dead?
http://www.zdnet.com/blog/microsoft/will-there-be-a-silverlight-6-and-does-it-matter/11180
These are often from end-clients, managers, architects or even consumers. Sometimes also from guys who have little exposure to Silverlight; but still want to engage in the conversation as it is "happening" talk 
Let me address that by admitting that i am a techie who view any technology as it is irrespective of whether it is from Open Source / MS/ Adobe etc. I have no stakes in the conversation except my view towards it.
But First:
Why change? Why Silverlight might not required?
Silverlight works as a plug in to browsers.
Plugin model works very well (think flash / Flex / Silverlight) on a desktop environment. Suddenly we are in a world of smart phones/ tab devices where plug-ins are evil. Well, at least IPad / IPhone consider these as evil. So as plugin Silverlight / Flash may not have bright future as it does not scale well to form factors like phones and tabbed devices.
Desktop v/s Tab devices / phones
Silverlight is supposed to be a cross browser / cross platform. It does works well on Windows / Mac machines; but that is related to desktops only. Now-a-days cross-platform have all together a different meaning. It not only means cross OS it also means across devices like IPad, IPhones, tabbed devices, etc.
There is a better alternative to plug-ins – HTML5 / CSS3
Html5 have changed the game. Its not only MS, who have changed the strategy, hugely successful plugins like Flash are also discontinues in favor of Html5. See this: Adobe to More Aggressively Contribute to HTML5 http://blogs.adobe.com/conversations/2011/11/flash-focus.html
The world now need "Apps", No programs, no suits, no installers.
The devices are smart with gyroscope, motion sensors, GPS etc. There is a need and a huge untapped market for Applications which can use these features for something useful. Application model have worked wonders for Apple.
Ok agreed, World needs a change, where is my Silver Bullet???
THE BIG QUESTION- Is Silverlight dead?
Silverlight as plugin in desktop is alive and kicking.
We now have a Silverlight 5. The investments done on this is safe as it continues to grow. The thing which changes is that before choosing Silverlight; consider Html5 very seriously. Silverlight works very well in scenarios where Rich Media is required or there is a need for 3D / or frictionless install(Silverlight can run out-of-browser)
Silverlight has out grown itself
Silverlight is used for developing rich web apps, out of browser apps (works very well for in-house intranet applications), SharePoint controls and it is the PLATFORM for developing applications on Windows Phone 7.
It may not be not Silverlight, but it’s Silverlight spirit survives and now is natively supported by the operating system to boot
All Principles of Silverlight, including the use of XAML as a markup language, C# and VB .NET as programming languages, a streamlined .NET CLR (Common Language Runtime) profile, XAP packaged deployment over HTTP and a sandboxed security environment, are fundamental to WinRT; the new runtime in windows 8.
XAML is “a first class citizen” and the native approach to developing Metro-style apps on Windows 8.
All my r&d and people who deeply work on Silverlight have successfully compiled existing SL code against WinRT just by changing names of namespaces
Silverlight developers – Rejoice
The skills as SL developers can be used to develop app on Windows Phone.
It can be used to develop applications on web (desktop environment)
It can used to develop Metro apps on Windows8
Windows Phone 7 and Metro Apps works on Application platform methodology which provides very good monetization opportunities
Silverlight is far from dead. Trust me, If you are a Silverlight developer your hands are full; others have a big learning curve ahead before they catch up.
Update:
SL5 is now officially supported till Dec 2021. Here is the link…
http://support.microsoft.com/gp/lifean45#top
”Silverlight 5 will support the browser versions listed on this page through 10 Dec 2021, or though the support lifecycle of the underlying browsers, whichever is shorter. As browsers evolve, the support page will be updated to reflect levels of compatibility with newer browser.”
