The Download: how ChatGPT was made, and a boost for infertility treatment

When OpenAI launched ChatGPT, with zero fanfare, in late November 2022, nobody inside the company was prepared for a viral mega-hit. It was viewed in-house as a "research preview," a tease of a more polished version of a two-year-old technology and a way to iron out some of its flaws. But then it absolutely blew up. The firm has been scrambling to catch up--and capitalize on its success--ever since. To get the inside story behind the chatbot--how it was made, how OpenAI has been updating it since release, and how its makers feel about its success--our senior AI editor Will Douglas Heaven talked to four people who helped build what has become the most popular internet app ever.