Will C9 be incorporating Silverlight 64 bit prior to the Silverlight 5 RTM?
We already do support it for people running 64 bit browsers. I just downloaded the Silverlight 5 Developer Runtime (64-bit version), then went into IE9 64 bit and C9 videos playback fine.
Direct link to installer: http://go.microsoft.com/fwlink/?LinkId=227576
Also available on this page: http://www.silverlight.net/downloads listed as "Silverlight 5 RC Developer Runtime (x64) for Windows"
I recall that on 32 bit IE there was a prompt to install Silverlight. In the current form the browser just defaults to playing the video via HTML I presume. There is no prompt to download the newly released Silverlight 5 which now works with 64 bit IE.