The mobile version of Habbo Hotel, the virtual game aimed at teenagers, has registered almost a million users with almost no marketing, VentureBeat reports. Mini Friday, which is the mobile counterpart to Habbo Hotel, is an example of a site that’s been able to crossover to mobile, without being held back by all of the hoops typically associated with re-purposing online content for mobile phones. What’s particularly fascinating about Mini Friday’s growth rate is the fact that the application is restricted to users 18 and older, it requires a download and registration, and it only runs on some Nokia (NYSE: NOK) S60 phones.

VentureBeat’s Matt Marshall caught up with Habbo Hotel’s co-founders Sampo Karjalainen and Aapo Kyrola in Helsinki, where they talked about life under their parent company Sulake, and the general momentum they are tracking worldwide. Habbo, the PC version of the virtual world, has 100 million members; plans to turn a profit this year with $50 million in revenue; has 300 employees in offices in 15 countries; and has raised $25 million in venture capital from Benchmark Capital, 3i Group and Elisa Group, a Finnish telecom company. The site makes money by charging for virtual goods – things like furniture, new room layouts, avatar clothing, hair styles and tools. The mobile version, Mini Friday, which is still in beta, originally launched in 2006, but following its climb to 1 million users, the founders are planning to take it out of beta soon. The company is also working on an iPhone version.