How much shoppers will welcome a blizzard of ads as they peruse virtual aisles remains to be seen. For supermarkets, the big questions are how much they will sacrifice direct relationships with customers who access them via Instacart, and who will reap most rewards from the ad bonanza. Ms Simo insists the benefits will be shared between Instacart and its partners. But, says Stephen Caine of Bain, many of America’s big supermarkets are building their own online platforms to rely less on Instacart. The fightback has begun. It may not be a Hundred Years’ War. But it will be a long one.