Rockstar has done well to keep this under its hat - Grand Theft Auto Online is bigger than anyone expected.
At any given time, you'll be playing online in the GTA V world with up to 16 other people, but sans lobby. In much the same way Rockstar pioneered streaming world data in action games with GTA III, it not plans to stream online opponents, matching you to those of a similar skill level, prioritising friends and crew members.
Players can engage with each other in an ad hoc manner, forming impromptu friendships and rivalries, or can hook up and plan heists (a major component of the single player aspect of GTA V) in multi-tiered stages.
The level of customisability and number of things you can spend money on are immense, with everything from property purchases to stock options being brought over from GTA V's single player.
Free roam and specific matches are now integrated, so players setting up for a race can potentially be gatecrashed by a hooligan in a police chase, while those with cushy apartments can watch the madness from a direct feed from the police choppers on their TV.
It feeds elements of all of Rockstar's games from this generation into one big experience.
Rockstar has been careful to deliniate between GTA V and GTA Online, indicating that future (or perhaps even past) iterations of GTA will expand to this unprecedented multiplayer service, which the company claims it will be 'constantly' updating with new content.
Check out the video below: