Habbo Hotel Gets Cash, Goes Mobile: "Sulake can stand to make significant money off porting Habbo to cell phones. The company plans to work with handset manufacturers, to preinstall the mobile community, carriers, to boost mobile portal traffic, and other entertainment brands to distribute content wirelessly."
Not convinced, myself. From the little I've used Habbo it seems to require a lot of attention - it's very immersive, which seems to me to be the opposite of what works well on mobile.
But these guys no doubt hire smart people who've thought about this sort of thing.