We exploit scanner data to track payment choice for grocery purchases for a large panel of households over three years. We show that households focus most of their expenditures on one or at most two of these instruments in choosing between using cash, a check, or a card, and they very rarely...

56K modems were introduced under two competing incompatible standards. We show the importance of competition between Internet Service Providers in the adoption process. We show that ISPs were less likely to adopt the technology that more competitors adopted. This result is particularly striking...