Habbo Hotel, the world's largest virtual world aimed at teens, is turning 10 in 2010. Simultaneously, Habbo is doing better than ever, even in the face of greatly increased competition. The game sees over 15 million users each month, and gathered 50 million euros of revenue in 2008, mostly from micro-transactions. The service has seen multiple fundamental changes over the years to accommodate for competition and changed end-user expectations, not least of which have happened in how the virtual economy of the service is structured. The talk walks you through how the game has changed over the years from the perspective of the game's economic system. Topics covered in the talk includes discussion on how valuable should a virtual currency be, how many currencies does it make sense for a virtual world to have and what are your users looking for in virtual goods when making purchase decisions.