Do you really need age, gender and country to sign up? Remove that signup form and replace it with a "Try" button that lets people use the service. Attach the registration code to the onunload method of the user's "home" page, popup a dialog asking them to register to save their settings (requiring only login-name, password and email "in case they forget their password", for now.) Ask more personal questions to help them improve their experience or find others like them. You can even get home address once you are big enough and start launching parties or local events.