The tepid debut of Britain’s dominant food-delivery app signals doubts not only about the gig economy but also about London’s ability to lure tech-firm listings. Chinese officials love to deploy “cloud seeding” to water the country’s parched lands, but even if it works, it distracts from better water-management policies. And why tweets so often come back to haunt their authors.

For full access to print, digital and audio editions of The Economist, subscribe here www.economist.com/intelligenceoffer