People used get together to show their vacations as slide shows with a projector to family and friends and make a "party" out of it. If they were really fancy, they might have even had 8mm motion film to show. It always felt really strange to me then as a bit of bragging and showing off. I was told it was a bit of living vicariously through other's adventures, but it just felt weird to me. Maybe that's why watching other people on social media gives me the same creepy vibe.