YouTube has announced the addition of a new feature that could be useful for online discussion about videos. The new feature is the option to record a video response to a video using your webcam. After every video that you watch you can click the “post a video response” link just below the video player and record your response.

This only works on YouTube itself, not on embedded video players.

Applications for Education
If you teach an online course or in a 1:1 environment, the option to quickly post video responses could be a good way to build a conversation about a video. In particular, I think this would be good for courses that frequently discuss news stories and or public policy issues.

Here are some related resources that may be of interest to you:
VoiceThread Highlights
PBS Launches a New Video Portal
20+ Educational Alternatives to YouTube