Originally made for business purposes, this is one of the best technology tools I have put to use in my classroom in the last few years.
Step One is to name your room.
I post the link to my room. (It is always like this: todaysmeet.com/+the name of your room So my link would be: http://todaysmeet.com/trialanderror) Students go to the link on their computers and then they join the room and can comment on the day's class. (Particularly useful in discussing videos in class without interrupting the video. Everyone will need a computer to be able to comment/question and to follow the thread of discussion.) It works like Twitter. They have 140 characters and can comment as often as they like.
Besides using this during films, I love using this when the students are listening to a reading. I project the "Today's Meet" room on the white board. Everyone in the room has the opportunity to use the discussion thread if they need it.
To get a picture of the room: the students have the book, an audio tape of the book is running, Today's Meet is projected on the whiteboard, and (some) students have a computer and are on the Today's Meet link. You might think it is too much for the students, but this is a generation of multi-taskers.
There are two ways I can work this:
1. The students can use the link to ask questions about things they don't understand or confusing vocabulary. I can respond to questions on the link as quickly as they crop up. There is no interrupting of the story to do this.
2. I can be the only person on the Today's Meet room, and I can guide their reading by typing things I want them to notice or think about as the story progresses. They can refer to the whiteboard projection of the Today's Meet conversation or not. It is their choice.
To be honest, a combination of these two ways works the best for me. Guiding them, but answering questions that crop up makes it a great tool for everyone. It reaches the students who need the most help, guides the students who let their attention drift, and gives the great students a chance to share their thoughts.
If you haven't tried it yet, I highly recommend http://todaysmeet.com I don't think you'll be sorry that you tried it!