Traditionally, what happens in Vegas stays in Vegas. Not this time, though. Microsoft may have chosen Sin City as the venue for the launch of its Silverlight browser plug-in, but it's hoping that the word about Silverlight will spread around the globe.

On the face of it Silverlight is an alternative to the Flash Player. It has support for high-quality video streaming - up to 720p high-definition resolution, if your broadband pipes are broad enough. And it also supports images, vector graphics, animation and text.

Like Flash, it's cross-platform, so it runs on Macs as well as PCs. And like Flash, it's cross-browser, so it runs in Firefox and Safari as well as in Internet Explorer 7. Microsoft also plans to bring Silverlight to Windows Mobile phones and to the Opera browser. And the open source Mono project will bring Silverlight to Linux too.

This is good news for anyone who's been turned off by streaming media sites and their "Sorry, IE only" bouncers. Through Silverlight, media streaming sites that currently cater for IE users can now easily cater for Firefox and Safari users too.

We've already seen some excellent examples of this in action, such as live sports streams and high-definition movie rentals from the likes of Netflix. And anything that makes more sites get rid of their "No Macs" policy is fine by us. But this is just a small part of the Silverlight story, because Microsoft has much bigger things on its mind.

Work in progress

Version 1.0 of Silverlight - which is currently in beta, with a final release due in the summer - takes care of the multimedia stuff. But Microsoft has also built a second version with the cunning name of 1.1. This version is in alpha, which means it's still very much a work in progress. It adds serious programming power via the .NET framework.

This is the programming system built into Windows. It's what software companies use when they write Windows applications. Microsoft has essentially chopped it up into little bits and shoved the most useful ones into Silverlight.