I created Togethr.TV in 2013 (https://togethr.tv). People can watch videos together and chat (text/audio) and some other features. It never took off much unfortunately.
I didn't touch the code since some time already but it is still working fine, the site is currently having about 15k monthly users.
I started https://togethr.tv/, a website where you can watch synchronized videos with your friends. Other features include text and audio chat. I wanted to promote it, but I never did. Average of 1000 unique users / month. You can contact me on [email protected].
Togethr.TV : https://togethr.tv
With our website, you can watch videos in real time with your friends. Audio chat is also supported. It is awesome because it makes it very easy to show specific part of a video to anyone! :)