Stream is a service that is attached to a gaming console ( demoed on a xbox one) It helps users in a overlay that gives the user serval options, a key idea is adding video chat to the side of the gaming screen as it lets the user see each other what this does is encourage people to be more social as they can see who they are talking too. You can also do a lot more as well as spectating games to watch other people play, stream to accounts at one time such as youtube and twitch, set up clan vs clan events when everyone is online while in game for faster response and training which monitors the way the player plays the game and then give them tips on how to improve or if they are new to the game it gives them a in game tutorial so they learn as they go.