Well this was interesting - Microsoft have embraced Mono's Moonlight as their official Linux version of Silverlight. From Scott's blog post:

Over the last few months we've been working to enable Silverlight support on Linux, and today we are announcing a formal partnership with Novell to provide a great Silverlight implementation for Linux.  Microsoft will be delivering Silverlight Media Codecs for Linux, and Novell will be building a 100% compatible Silverlight runtime implementation called "Moonlight".

I think it's interesting for several reasons -- Microsoft partnering with Novell to release an open-source version of Silverlight, when the Windows / Mac one is closed; and that they are planning to make Moonlight "100% compatible".

100% compatability is a pretty strong statement. I know that the Mono project has been aiming for that for a while, but has had to work around bugs or inconsistencies in the CLR to achieve it. I wonder how Microsoft is helping Novell achieve that?

Miguel has some details on who was involved from within Microsoft, and how the test suite will be shared between the two companies.