Roblox hits 100M monthly active users, bigger than Minecraft
Both of my kids played a lot of Roblox until we banned it. They easily became obsessed and were violent when removed, even with a tightly controlled schedule. They would try to connect to offer WiFi networks to get access and would steal our phones to get access. We ended up having to detox them like it was a drug.Beyond that we found that the openly mod-able nature of the game allowed some remarkably disgusting 3D models and game modes.  Just Google it.  It was not hard to find a room with 50 kids holding adult store items and doing extremely inappropriate things.The system is also rife with predators. One game let them share pictures somehow.  Some guy was asking my daughters to send them pictures of their feet.  Try to censor that request in chat, I guess.This if course sets aside the caste system that is built on their in-game currency. Scammers can convince your kids to trade their favorite items away in a "trust trade".Roblox is not appropriate in my experience.