The ClassDojo screen can be projected on the IWB so that students can view their points and see when a reward is given. The teacher has the option to show both positive and negative rewards. Another nice feature is the ability to create your own rewards based on the need of your classroom. You can also choose to have an audible tone accompany a reward.
ClassDojo is such a fast and efficient way to record behaviors. I use the iPad app, so behaviors can even be recorded when we leave the classroom. At the end of the day I make comments on a students page if necessary. On Friday, the two students with the most points get a prize from our class treasure box get to pick a new avatar. (Each student has a cute avatar next to their name on the screen.) I also send individual reports via email to parents requesting them. (An introduction letter explaining ClassDojo, along with a request form was sent home at the beginning of the year.) This process only takes a few seconds! I reset all points back to zero for the new week. (This is optional.)
The ClassDojo folks are very efficient at answering any questions. They also have an ongoing format for teacher input and are continuously making changes to their product based on this input.
Here is the link if you would like to take a look at this great web tool:
I would highly recommend it!