Open Instagram. Scroll through TikTok. Browse X, Reddit, or YouTube. Something unusual has happened. Instead of chasing the newest trends, millions of people have suddenly started looking backward. Grainy selfies. Snapchat dog filters. Flower crowns. Pokémon GO screenshots. Vine compilations. Blurry sunset photos with heavy Valencia filters. Songs that dominated every party in 2016 are climbing playlists once again. The internet has become obsessed with one particular year.