https://www.gamespot.com/articles/gta-online-just-set-a-new-player-record-four-years/1100-6456060/

Grand Theft Auto Online, the multiplayer mode for Grand Theft Auto V, had its "biggest year" ever in 2017, developer Rockstar Games has announced. The studio announced this in a blog post recently (via IGN), though it didn't say if this achievement is based on player numbers, revenue, or some other metric. For December 2017 specifically, Rockstar said more people played GTA Online than ever before in the game's history.

This is extremely impressive, given that GTA Online launched more than four years ago, in October 2013. It is exceedingly rare for any game to have that long of a tail. GTA Online's ongoing success can no doubt be attributed to Rockstar's impressive commitment to launching new updates and activities on almost a weekly basis.