The simple joy of a social network most people forgot about years ago

Hello again and welcome back to Fast Company ’s Plugged In . If you owned a smartphone a decade and an half ago and were into cool new apps, there’s a more-than-decent chance you tried one called Foursquare . The best known of a then-new breed of location-based social networks, it let you check into places you visited in the physical world, and see where your friends were checking in.