Comment by MaintenanceMode

If you're part of a particular subculture, like sailboat cruising, nearly all of international sailboat cruising takes place on Facebook. There are pages for every town, anchorage, marina, etc that you will encounter. Often that is paired with a WhatsApp group where people have conversations and coordinate activities. When you sail from city X to city Y, you join that Facebook group and you learn where to do laundry, where to get groceries, etc. You stay on these groups and the whole community interacts there for many years. There are other places this happens but Facebook is the main source of this type of information sharing.