Great Video, I have been thinking why people do not use voice msg sending instead of typing. I bet that will even reduce the car accidents.I was using with MSN chat app at one point but as you said you have to install an app to make it work.

Just a small feedback for your video, if you are not on IE with silverlight the following message pops-up and gives you alternative, Most of us may only read the first sentence, and some may read rest and click.

"We've upgraded our Silverlight player so we need you to upgrade your plugin!"