Unlike most highly commercialized free-to-play kids' virtual worlds, Roblox started as an outgrowth of technology designed to simulate physics. It's a pure physics-based play space; kids arrange the blocks into LEGO-like structures, and others can access these spaces as they wish. Rather than a virtual world, it's a collection of user-generated spaces: in terms of how the site is set up, it's almost like a YouTube of play.
When its creators put it in front of kids as part of an educational package, they quickly noticed how much fun the kids were having with it, and moved to develop it into a product with that audience in mind. Now, Roblox has launched and found an organically growing audience, finally reaching the point where its first promotional deal, with Disney, has gotten off the ground.
Gamasutra recently sat down with David Baszucki, founder and CEO of Roblox to find out more about the project.