As testament to just how damn popular/important Valve's Steam platform has become to the PC market, recently over five million people were logged into the service at once.
The milestone was first achieved last month, while the service's notorious holiday sales were going down, but it's hit it again and again since, as recently as January 2.
The most popular game, and one that's helped propel the platform towards the milestone? Skyrim, of course, which even now is boasting three times the players the next most popular game (Team Fortress 2) can muster.
Steam hits five million concurrent players [PC Gamer]