Late last year, Zhang Xuan’s small beef noodle joint in Shanghai suddenly began seeing a dramatic surge in orders. Sales over the past few months have been 50 to 60 per cent higher than normal, he estimates. The driver? The new Street Stars feature on Chinese tech giant Alibaba Group Holding’s Amap mapping app, which listed Zhang’s eatery as the fourth best restaurant in Shanghai’s Changning district. Prominently displayed on Amap’s main page, the system uses artificial intelligence to rate...