I read an article about a month ago on when watching a video or movie in class, teachers were using a chat room to simultaneously discuss the movie.
Tiny Chat is only one of many sites where you can create temporary chat rooms for the class and share the link to all of your students. At the end, many of these chat rooms disappear and the info gets cleared.
What I liked about Tiny chat is that is also has the ability to show webcams, share Youtube videos, and you can create a whiteboard to share with the group so they can do some brainstorming.