Post Comments while watching a Youtube video

I want to embed a youtube video on a webpage. I need a box to type a comment about the video as it plays. All comments will be collected and marked with the time the comment was posted relative to the movie time. Then when the movie is played by the next person, the comment will be displayed when that part of the movie is seen again. Also, the next person will be able to add comments of there own. All comments will be combined together and displayed at the correct time during the movie.