On paper, it sounds like business suicide. Offer up the core of your gameworld and a wealth of its content for free, to anyone willing to give it a taste test. Its roots are in the ’90s, an extension of the razor blades business model, emerging in gaming from the need to combat piracy in certain territories. It found its way into the west most memorably in Jagex’s RuneScape, an MMORPG that launched, completely free for registrants, in 2001. Free-to-play is a draw for one big reason: the numbers add up.