Not factoring in Valve games, GTA 5 is the new king of concurrent player numbers on Steam.
GTA 5 is very popular on PC, even more popular than games like Skyrim in its heyday. The number of concurrent players for GTA 5 has peaked today at 301,246.
This makes it the only non-Valve game to ever reach that record, beating Skyrim's record of 280,000, which was also achieved on launch.
The numbers are all the more impressive when you consider the phenomenon that Skyrim was, and the fact that this is the third time GTA 5 has been released.