On the back of the incredible success of the early access battle royale game PlayerUnknown’s Battlegrounds, Steam has surged past a milestone itself- 15 million users concurrently online. To be clear, because this has been a point of confusion in the past, this does not refer to the total install base on Steam, just the total number of Steam users online at the same time.
15 million is more than the total number of Wii U consoles or PS Vita handhelds ever sold. It’s an incredible number of players, all online, playing at once. As can be suspected, the top played game when this happened was in fact PlayerUnknown’s Battlegrounds. Grand Theft Auto V, Rainbow Six: Siege, Warframe, H1Z1: King of the Hill, and Football Manager 2017 are other games that were being played by players at the time (as was, of course, Team Fortress 2).
Of course, with the release of several highly anticipated PC games, such as Divinity: Original Sin 2 earlier this month, we can presume that Steam will be able to maintain this kind of momentum for a while to come now.