In technology, as in life, history doesn’t repeat itself. But it does rhyme. The share price of Chewy, an online pet-food retailer which has just listed in New York, shot up by more than 50% on June 14th, its first day of trading. To seasoned investors it brought back memories of Pets.com, Chewy’s ill-fated predecessor, which collapsed nine months after it debuted on the Nasdaq exchange in February 2000. It became emblematic of the first dotcom bubble, when loss-making startups fetched stratospheric valuations—until they didn’t.