ShareTube - Watch YouTube, synced with friends.
Watch2Gether - Watch2Gether is an app that allows multiple people to watch the same content simultaneously and interact with each other while watching.
Picaboo - Picaboo is a web-based image publishing and printing service that allows you to create personalized photo books, cards, and scrapbooks.
Metastream - Watch streaming media with friends
&chill - Watch YouTube & Twitch videos with people online
Kosmi - Digital Hangouts Reinvented