Interactive Video Lectures

So I've started watching video lectures on MIT's OpenCourceWare (OCW) site. Its really nice to be able to watch a lecture when you are in the mood to pay attention. Its likewise great to be able to pause the lecture when you are interrupted or if you need a break for any reason. The only thing missing it seems to me is the ability to ask questions.

So I thought about it and it seems that it wouldnt be to hard to correct that. If the lecture videos were flash based, it would be great to be able to hit a 'question' button at a certain point in the lecture and either type in or record your own question. The lecturer would get a notification (via email or otherwise) that a question had been entered and he could record an answer that would be either inserted into the video of the lecture automatically or shown as optional content when students reached that part of the lecture.

There's lots of great additional things that you could do around this idea, like have Atom or RSS feeds for students to see new questions&answers that have been added. Multiple similar questions could be answered at once, and the quality of the lecture would go up as the lecturer would have the most appropriate feed back and an easy way to reintegrate the feedback into the already completed lecture.