Well, that didn't take long: Valve has made its Steam Broadcasting feature official, dragging it out of its quick stint as a beta part of Steam.
You can now update Steam, if it hasn't already been updated for you, and change your settings if you want Broadcasting to be enabled. This will allow your gameplay to be broadcasted to friends when you start gaming, which is an alternative to the super popular Twitch service, that was recently purchased by Amazon for $970 million.
Steam Broadcasting will only broadcast video by default, but you can also stream other applications from your computer if you allow it in the settings. Broadcasting will also take in your computers audio, too.