Heartbeat - Listen to music with your friends together, on Spotify
ShareTube - Watch YouTube, synced with friends.
Liyo - Stream your favorite music live with friends 🎶
Showgoers - Showgoers is a website dedicated to watching Netflix movies together with friends or loved ones who are not sitting on the same PC.
TuneMeet - Chat with people who are listening to the same song
Netflix Party - Netflix Party is an extension for watching Netflix remotely with friends and family for movies nights with that long-distance special someone.