Togetherly - Watch Youtube with friends
Dead Simple Screen Sharing - Simple screen sharing and audio conferencing software.
ShareTube - Watch YouTube, synced with friends.
Muzzle - Silence embarrassing notifications while screensharing
Showgoers - Showgoers is a website dedicated to watching Netflix movies together with friends or loved ones who are not sitting on the same PC.
Surfly - Simple, Fast, and Secure Co-browsing