What Silverlight 4 means for you

eBay Silverlight
The future of Silverlight 4: you wouldn't know the eBay Simple Lister wasn't a Windows app

Silverlight does a lot more than playing video; it's on 60 per cent of all PCs worldwide, apps from eBay listing tools to social networking clients are showing up – and Silverlight runs on Macs, PCs, Linux (through Mono) and soon on Symbian, MeeGo and Windows Phone.

Microsoft launched a release candidate of Silverlight 4 this week at the MIX conference and while you won't want to upgrade just yet (the RC is aimed at developers, the final version will be here next month and some apps built for Silverlight 3 don't yet run in the RC), when you do you'll get apps with lots more features.

The Silverlight plugin is still only a 5MB download and as well as running in IE, Firefox, Opera and Safari there's now a version for Chrome.

Silverlight 4 applications start more quickly and Microsoft claims they run 200 per cent faster than in Silverlight 3. Long lists scroll faster; Corporate Vice President Scott Guthrie told us he asked his team to show him a list box with a million items scrolling at 60 frames per second.

The Deep Zoom super-fast super-smooth zoom into images (that can turn into other images when you get to the detail) now works with the Pivot tool for exploring huge amounts of data (first seen at PDC last year).

Multi-touch, HD video

Apps can use multi-touch and if you're playing DRM-protected media in Silverlight that can now include H.264 – the support for a protected video path from the internet to your screen makes it likely that we'll see more commercial video services.

If you're watching HD video or playing a game and you want to do it full screen on one monitor while you have web pages or work applications on the other, you'll like the option to pin apps full screen to one monitor.

In previous versions you could have a Silverlight app full screen on one monitor but it would jump straight back to normal size as soon as something happened in a program on the other screen (like you answering an email).

Right-click on a normal Windows app and you get a context menu; with Silverlight 4 you can get that in an app too, instead of just the plugin menu; this makes Silverlight apps much more powerful and controllable.

Apps can have copy and paste and drag and drop too. They can now use a webcam and microphone for streaming or recording; expect to see video conferencing and chat apps built in Silverlight.

Seesmic Desktop going to Silverlight

Silverlight let apps run in their own window, outside the browser – and even when you aren't online. Seesmic has just announced that it's moving its popular Seesmic Desktop Windows app to Silverlight – which means it will run on the Mac too.

With Silverlight 4 those apps can be more powerful; they can run HTML directly and use notification windows to tell you something is happening. If the Silverlight app plays DRM-protected media, you can do that when you're offline as well. And if they're digitally signed, 'trusted' apps can read and write files to the user's Documents, Music, Pictures and Video folders (on Mac as well as Windows).

They can work with peripherals and send information to other apps, so your Silverlight app can open Outlook to send email or export directly to XML. And if you're running a Silverlight game full screen, you finally get full keyboard access – so you can have proper keyboard shortcuts for game actions.

They can also get rid of the Silverlight 'chrome' and have their own look and feel The Silverlight Facebook app and the eBay Simple Lister announced at MIX do this, leaving little trace that you're using Silverlight at all. With the best Silverlight apps, you might not know it's Silverlight.


Mary (Twitter, Google+, website) started her career at Future Publishing, saw the AOL meltdown first hand the first time around when she ran the AOL UK computing channel, and she's been a freelance tech writer for over a decade. She's used every version of Windows and Office released, and every smartphone too, but she's still looking for the perfect tablet. Yes, she really does have USB earrings.