Habbo

Habbo (formerly Habbo Hotel and Mobiles Disco) is a social networking service and online community aimed at teenagers. With users over in 150 countries, there are over 278,000,000 users, which 90% is users that has age of 13 to 18.

Gameplay
Habbo's main feature is hotel, it can be accessed by if you log in, there are many rooms to choose, like jobs, games, hangouts and many more.

There are 3 currencies on Habbo: Credits (or coins) and Duckets (free currency). Diamonds is a exclusive currency that you can buy with HC (Habbo Club).