 It is common in science for models that are practically clumsy fits to their original problems to turn out to furnish highly efficient solutions to new problems thrown up by technological change. The internet has created an environment for applications of matching algorithms — travellers and flat renters, diners and restaurants, students and tutors, and (regrettably) socially alienated people and purveyors of propaganda and fanaticism — that could have been designed by a theorist at any time since Shapley’s original innovations, but would previously have been practically impossible to implement. These applications of cooperative game theory are often applied conjointly with the noncooperative game theory of auctions  (Klemperer 2004)  to drive market designs for goods and services so efficient as to be annihilating the once mighty shopping mall in even the suburban USA. Why are hotels far more profitable and easily available than was the case in all but the largest cities before about 2007? The answer is that dynamic pricing algorithms  (Gershkov and Moldovanu 2014)  blend matching theory and auction theory to allow hotels, combined with online travel service aggregators, to find customers willing to pay premium rates for their ideal locations and times, and then fill the remaining rooms with bargain hunters whose preferences are more flexible. Airlines operate similar technology. Game theory thus continues to be one of the 20th-century inventions that is driving social revolutions in the 21st, and  Samuelson (2016)  predicts a coming surge of renewed interest in the deeper mathematics of cooperative games and their relationships to noncooperative games. 