We now know that the circle is SteamOS. Then, the second announcement would be "SteamOS in a box", and the iconography of the third announcement is "two SteamOS". This probably has something to do either with playing or sharing with friends, or more details on streaming games from another machine on the network.
Come to think of it, Dota2 just mentioned recently an update that either just came out or is coming out in a few days that would allow you to play a Dota2 LAN game. Perhaps the third announcement will be more along the lines of sharing a game only you own with friends on your LAN, for that sort of purpose?