Valve is making a move into livestreaming with the launch of the Steam Broadcasting beta. The service will allow gamers to watch games their friends are playing from within the Steam client, and also to stream their gaming sessions publicly.
The integration of Steam Broadcasting into the widely-used Steam client will, in theory at least, greatly simplify the process of livestreaming games. Streamers need only select who can watch them play and whether or not they must first make a request, after which the system will handle everything automatically: Selecting "anyone can watch my games" will make the broadcast visible on the game's Steam hub, and private broadcasts will start and stop automatically during play as necessary.
There are a few limits to the system, as the Steam Broadcasting FAQ explains, including browser support, which is currently limited to Chrome, Safari, and the Steam client. There's no way to invite anyone who isn't in your friends list, and broadcasts aren't currently being archived, so there will be no record of your digital glories. There are also limits on the bandwidth being allocated for the beta, so you may occasionally run into a "Broadcast unavailable" message.
It's hard to say yet whether this represents the first step in a concerted effort to slice off a big piece of the livestreaming pie, which would put Steam Broadcasting in direct competition with Twitch, or if the intent is simply to maintain engagement among Steam users by bolstering its value as a social network. As it stands, it feels like it's about connecting with friends more than broadcasting e-sports to large audiences, and it may well stay that way, but I can't imagine that somebody, somewhere, isn't considering the possibility of going bigger.