The idea is that both need to consider likely meeting points. Natural choices would be famous landmarks or meeting spots. Outside the #EmpireStateBuilding? The lobby of #GrandCentralStation? There's maybe a few dozen spots people might go for. But that's a lot less than the number of buildings in #NewYork.

And a meeting time? Maybe noon, or 6pm. Maybe not 2.27 or 4.38. There seem to be preferred choices. #Schelling called these #FocalPoints. Today they're often called #SchellingPoints. (4/n)