No accounts are needed to use Kalidoface, you maneuver to the site and give it access to your camera. From there, you can pick different avatars. As you speak and move your head, the on screen avatar does the same. Pretty cool.
While the site has a built in conferencing tool, I think the main use of Kalidoface in the classroom would be for students to create their own multimedia avatars for projects. By recording the screen with a screen recorder, they would get a video that could be used in presentations and their own videos.
I could also see the site being used by students who are apprehensive on recording themselves. With Kalidoface, they can have someone else with their voice.