KGS has a “teaching game” category, the definition is
In a teaching game, the player with white has the ability to stop the game, make annotations, try variations, and restart the game. See Tools for Demos, Teaching, and Review for more information. Unlike other game types, in a teaching game, players can see comments that observers make about the game while it progresses. The chat line in a teaching game can be supplemented with audio if the teacher has a Teaching Account. A teaching game has no effect on ratings.