I would like to have two streams. One being traditional streaming video and another being text. I will also build an interface that allows the user to create the text portion while watching the video. The context of these videos are usually that of an individual being filmed doing a presentation and later the next day for example, a coach will make text annotations (structured data is a plus) with the result being the text stream.

It seems this is possible with Silverlight (see the article in the latest MSDN). However, what other methods are there if any? If there any, please give the reasons for why you are recommending them. Thanks.

Also, I would prefer something that inst a software as a service hosted solution, but, dont let that keep you from giving an answer. Also keep in mind, the user shouldn't have to do any re-encoding of the video source, the text stream should be separate with someway to synchronize a coach's comments to an arbitrary time stamp in the video.