in an effort to expand it’s social dimension, YouTube just announced a new “real-time” service that tells your friends what videos you’re currently watching.
there’s actually a similar service that does this called tubetrail. all you got to do is install this as a browser plugin (currently works only with firefox only), this will then show you a page of all YouTube videos you’ve watched or watching! 
see more [news.cnet.com]
see more [news.cnet.com]
set it good 