Two decades ago in his book Bowling Alone, Robert Putnam famously described the erosion of social networks and social norms in the US that began in the latter third of the twentieth century. His research found that various measures of social engagement had declined precipitously—including religious participation, membership in community organizations, and the frequency with which people were inviting friends to their homes.1 According to Putnam, many of these trends have only worsened in the years since his seminal publication.2
