Ping allows you to notify your friends with a set of context-sensitive messages about real-world places - think of it like Apex Legends ping system for real life. For example, you can tap a Mexican restaurant on the map to say "Mexican food here!", or tap the Metropolitan Museum to say "Art Museum here!". Your squad mates will then receive a push notification that shows them the ping on a map and allows them to respond with "Yes", "No", or "I cant do that". Use it to coordinate meetups or propagate memes about the location of African countries - its all up to you, really.