Lofty aspirations for Facebook groups risk linking wrong people

It was half-time, February 2020, and the San Francisco 49ers were tied 10-10 with the Kansas City Chiefs; the biggest prize in American football was still all to play for. While the teams regrouped, Facebook was making its own big play. In its first-ever Super Bowl advert, the globe-spanning social network showed off a medley of Facebook groups relating to the word “rock”: extreme climbers in Utah, replica Stonehenge builders and a Rocky Balboa fan club gatecrashed by Sylvester Stall