Valve decided to compete with Twitch and launched beta testing of the new Steam Broadcasting service, which will allow Steam users to stream their gaming sessions and watch other gamers play.
Those who intend to stream gameplay only need to specify who can watch them (you can select the option “anyone can watch my games”), and whether they need to approve watch requests, after which the system handles everything automatically. Currently, the Steam Broadcasting beta works only in the Steam client, as well as in Chrome and Safari browsers. For now, you cannot invite people who are not on your friends list to watch, and broadcasts cannot be saved.
If the internet connection is not fast enough, users may see the message Broadcast unavailable. You can find details about the service on the official website.