If you are a member of YouTube you can now start using a new feature called active sharing. This allows other people to see what videos you have been watching and what videos you are watching right now.
“When you start Active Sharing, your username will appear to other users on the videos you watch. A list of videos you’ve recently watched will also appear on your profile page.”
It’s a pretty simple feature that will help YouTube users find people who share similar interests and to see what those similar people have been watching.