StreamParty works by
keeping all of the devices in sync when starting, pausing or seeking a video
Install the extension:
The extensions is available in the webstore
Go to a video on a supported platform
Currently StreamParty supports Youtube and Netflix. If you're on a supported video the StreamParty extension button switches from to
Login or Signup
Click on the extension button and then when first starting the extension you will be asked to Login or Signup
Create a Party
After Logging in if you click the extension button again you can start the party.
Share the Link
Copy the link and send it to your friends. They have to have StreamParty installed. Once the link is loaded, they have to click on the StreamParty extension button to join the Party
Watch the Video & Chat
You can now start watching the video and it will keep all of them synced to all possible actions, like pausing or seeking.