Twitch.tv, the popular game streaming service, got some competition yesterday when Steam's game broadcasting came out of beta. Steam, for the uninitiated, is Valve Software's game store/community/download client and is as close to a 'universal' PC gaming platform as there is (you can get Steam for Windows, Mac OS and Linux). How popular is Steam? Earlier this month they recorded almost 8.4 million concurrent users (8,384,528 to be exact) according to their stats page.
And now (almost) all those users can start broadcasting (streaming) gameplay. In order to be eligible you have to have made a purchase from Steam at some point, and not be banned.
Let's talk terminology for a moment. Steam refers to letting other people watch you play as broadcasting whereas Twitch calls it streaming. Steam (I assume) chose the term broadcasting so as not to confuse this service with their In-Home Streaming service. Steam's In-Home Streaming lets you use your powerful PC gaming rig to play games on a lesser system, say a laptop or a home theater PC. Data flows both ways and in this case you're actually playing the game, whereas with broadcasting you're just watching someone else play.
Hopefully that makes sense. In any case, I don't feel like Steam is a direct Twitch competitor because they come at broadcasting from a different angle. Whereas with Twitch a person decides to stream a game he or she is playing and then hopes an audience will come watch, with Steam you can see that a friend is playing something you're interested in and request that the friend let you watch.
You check your friends list, see that your friend is playing a game you like, then click through to that friend's profile page and you'll see a "Watch Now" button in the right hand column. Click that and your friend will get a pop-up asking if he or she wants to broadcast.
As the player, you can turn this prompt off so any friends can just jump right in and when they do, broadcasting starts automatically. You can even open it to public viewing. On the Steam client there's a Broadcast option under the Community tab but it hasn't been added to the website yet, however this link should get you there. No matter how you get to it, that page shows you all the folks streaming publicly.
I checked in with a buddy playing a game and it looked pretty good (I visited him via browser). He was broadcasting at 720P and told me he hadn't noticed any perceptible hit to his frame rate. Myself and a few friends were able to chat in a sidebar and the streamer, I'm told, sees this chat in a small 'ribbon' on top of gameplay.
Broadcast settings are under the Steam -> Settings menu in the Steam client. This is where you can totally disable broadcasting if you don't want to be bothered (on my account at least it defaulted to "Friends can request to watch my game"). On the other hand if you want to go all in you can set it to "Anyone can watch my game" and then if you tick the checkbox "Always show Live status" it seems like everything you play will be broadcast publicly. You can also choose whether to record input from your microphone, and even opt to record your desktop, which should be handy for broadcasting non-Steam games (just make sure to disable it when you're through). You can also set the resolution of your stream anywhere from 1080P down to 360P and choose the maximum bitrate (handy when playing online games, I'm sure, so your broadcast doesn't impact your gameplay).
Overall it seems like a pretty slick system, though I would've preferred that it was set to 'Disabled' by default. Unlike streaming to Twitch.tv there's nothing for you to set up; it just works. Twitch requires you to use 3rd party software to stream, which I'm sure allows for more control and is probably better for 'pro' streamers but I have to give Steam credit for making broadcasting super easy on this platform. It ought to get a lot of folks interested in sharing video of their games.