I'm not attending MIX '07 but it looks like we're announcing some good stuff this week. because the stuff I've been working on isn't ready to be announced yet but my coworkers have dropped some cool announcements. Today we announced Silverlight Streaming by Windows Live. To understand this announcement you first have to understand what Silverlight actually is.

From http://www.silverlight.net we learn

Microsoft® Silverlight™ is a cross-browser, cross-platform plug-in for delivering the next generation of .NET based media experiences and rich interactive applications for the Web. Silverlight offers a flexible programming model that supports AJAX, VB, C#, Python, and Ruby, and integrates with existing Web applications. Silverlight supports fast, cost-effective delivery of high-quality video to all major browsers running on the Mac OS or Windows.

If that is still too complex for you; you can consider Silverlight as being akin to the Flash platform but built with the .NET platform with all the attendant benefits (i.e. development with Visual Studio and access to a ton of languages). Now we know what Silverlight is, what exactly is Silverlight Streaming by Windows Live? Glad you asked.

From the blog post entitled New! Silverlight Streaming Service on the Windows Live Dev blog we learn about http://dev.live.com/silverlight which states

Microsoft® Silverlight™ Streaming by Windows Live™ is a companion service for Silverlight that makes it easier for developers and designers to deliver and scale rich media as part of their Silverlight applications.  The service offers web designers and developers a free and convenient solution for hosting and streaming cross-platform, cross-browser media experiences and rich interactive applications that run on Windows™ and Mac..
...
Microsoft® Silverlight™ Streaming by Windows Live™ can be used either directly from the administration web site or via a REST API. The API allows you to upload, update, delete, and invoke Silverlight applications using the Silverlight Streaming service. Click here to view the complete API reference.
...
While the product is in pre-release, storage and delivery is free up to 4 GB, with outbound streaming up to DVD quality (700 Kbps). As we move out of Beta, developers/designers will have continued use of the service with up to 1 million minutes of free video streaming at 700 Kpbs per site per month. Unlimited streaming will also be available for free with advertising, or with payment of a nominal fee for the service for use without advertising.

Not only is Microsoft giving developers a platform for building Rich Internet Applications (RIA) but it is also giving developers free streaming media hosting if they plan to use the platform to build a media sharing service. This is an interesting new wrinkle in the competition between Web application platforms. The response from Microsoft's competitors will definitely be interesting. I wonder if we'll see a partnership between Adobe/Macromedia and Amazon to bundle free usage of Amazon's S3 service if you are building applications with Flex or Apollo?