My two kids have been playing it, pretty steadily, for the past 3 years.
It is likely a combination of factors, but i'd the say the big ones are :
- The game is multi-platform and cross-platform : Everybody can play with everybody on most devices. My daughter plays from her tablet, my son from my PC. All of their friends are also playing.
- It's a social hub where users constantly publish new content, not a single game : Every other week, they seem to be playing a new thing. Those things are derivative from establishes franchises, such as The Sims, Call of Duty and other popular titles. A lot of it is trash, but some of them are very well made and attract a lot of players.
- The game is free. The only cash you need to put in is for cosmetics, aside from that, no play restrictions.
Granted, Roblox is not the only thing my kids play, but it has been a mainstay for a few years now.
Ninja edit : The current active player count for the game stands at a little over 145 million.
It’s the Minecraft kids that love these primitive type games. There’s some cool community multiplayer games that have no learning curve so it’s incredibly accessible to anyone. Not to mention it’s mostly free which is perfect for the demographic.
Try a Murder Mystery game. One random person is selected as the killer and has to kill players one by one and the only way to see who that is is when he brandishes a weapon or you witness him murder someone. Last survivor wins or if the killer wipes out the players - he wins. It’s surprisingly fun.