Beseda - Async video and audio messaging for remote teams
Jukebox - Collaborative music player
SuperNormal - Async video updates for remote teams
Juicebox - Spectacular HTML5 Image Galleries Made Easy
Popitalk - Popitalk is a website that lets you watch together with friends. You can watch Youtube, Anime, Movies, TV shows and Music together on Popitalk!
ShareTube - Watch YouTube, synced with friends.