Coordination, Communication and Common Knowledge: A Retrospective on Electronic Mail Game

Common knowledge plays an important role in coordination problems and coordination problems are central to many areas of economic policy. In this paper, I review some common knowledge puzzles culminating in the electronic mail game. These puzzles may seem distant from practical concerns. However, I then argue why insights derived from this literature are useful in interpreting empirical evidence of how people coordinate under uncertainty and in understanding the role of communication in coordinating behaviour.