one of the most asked questions i've been getting lately has to do with the silverlight streaming service provided by the windows live services. i think microsoft may have done ourselves a naming disservice with including "streaming" in the title. i think to most in the tech world, the "streaming" term implies a media file streaming like .asx files or streaming audio files, etc. that are consumed by some type of player.
well, silverlight streaming is a bit different in my opinion. first, the services hosts silverlight applications. the whole thing...xaml, media, etc. so it isn't streaming your media directly, versus streaming/hosting your entire silverlight application. sure, your application may include media, but it will also include xaml, etc. if you are hoping to upload a wmv or mp3 only to the service, you are in for a surprise...it isn't a youtube, soapbox, viddler thing.
let's say you have a wicked cool silverlight game you developed...you could put it up on silverlight streaming and enable people to embed it into their sites using the provided scripts. you can read an example about it on a previous blog post here.
one of microsoft's program manager's i think put it best...
Another major difference is that Silverlight Streaming is not designed nor tailored for end users. It is for web designers and Silverlight developers who wish to create 3rd party web sites taking benefit of the Silverlight capabilities on their site. They own the end user experience 100% (unlike Soapbox where whatever video uploaded to Soapbox has to be player in a Soapbox-branded wrapper/player). They create the end user interaction, the branding experience, the richness and interactivity, etc. You can also think of Silverlight Streaming as a platform to create end user-targeted services like Soapbox or MSN Video.
so take a look at the service and play around with it if you are a developer with silverlight applications.