Roblox box: Co-founder Dave Baszucki leans against a mockup of a video game action-figure set at the firm’s headquarters in San Mateo, California Image: Timothy Archibald for Forbes When Alex ­Binello ...

Surrounded by virtual cliffs and a cascading waterfall, dragon riders on Roblox’s massive online gaming platform immerse themselves in a memorable scene from “How to Train Your Dragon.” In the ...