In an update to the official Steam Universe community group
Valve has confirmed that they will soon be notifying the lucky 300 users selected to participate in its Steam Machines beta initiative, who will essentially be receiving a free gaming PC to help roadtest its new in-house range of hardware configurations, the innovative Steam Controller, and perhaps most importantly, the hugely ambitious Linux-based SteamOS.
Unfortunately however, logistical issues have purportedly caused them to reneg on the original plan to go worldwide with the beta program, so of the over 950,000 people that joined the Steam Universe Group for a chance to participate, only those located in the USA will now be counted among the 300 chosen to participate:
We’ve had to make the difficult decision to limit our beta to the U.S. only, because of regulatory hurdles. This was not our original plan, and it means we can’t collect beta feedback from Steam customers world-wide, which is pretty unfortunate. All things considered, we’re sure it was the right decision, because the alternative was to delay the whole beta beyond the point when we’d be able to incorporate any feedback into the 2014 products. This decision only affects Valve’s 300 prototype units; the commercial versions of Steam Machines that are for sale in 2014 won’t be affected by this. More information on those will be announced at CES on January 6.
It's not a total bust for us savages outside of the land of the free though, as Valve has also confirmed that SteamOS will be made available for download "when the prototype hardware ships", and that they are "due to leave the factory on Friday"; that's December 13 2013 PST.
Although Steam Machines are being designed with SteamOS in mind, they are still PCs capable of installing Windows like any other, and the SteamOS software can similarly be installed on a regular PC. Valve cautions that general users might want to wait until next year to start trying out SteamOS on their own computers, presumably so they can iron out some of the kinks first, but invites "intrepid Linux hackers" to have at it.
Finally, the update also reminded us that the beta launch of Steam's in-home streaming functionality is due to begin "soon".