" If you wish to watch a high definition movie together with your close friend who is far overseas, and be able to talk while watching it, most connection speeds will probably be insufficient to stream your desktop directly.
What you could do is both download the same movie beforehand, and simultaneously click "Play" button, and converse over some VoIP app while watching it.
However, if you wanted to pause the movie for a while, you might have a hard time resynchronizing the playback time.
An idea: a video player feature allowing to synchronize the "Stop", "Play", "Pause" button clicks, and timeline manipulations of two or more video players on remote computers over the web."
Probably, each player could have a button "Synch", clicking which would display a alert with a randomly generated secret code, and an entry field. Wishing to let another person to synch with you, you would copy-paste the code to them, and although they would also have their secret codes generated after clicking "Synch", they would enter your provided code to the entry field.
The cited portion of the idea is originally from http://www.halfbakery.com/idea/Video_20 ... eb_20Synch .