A Habbo-retro is an illegal site that mimics the appearance and style of the official "Habbo Hotel" website. The developer of the game, Sulake, is not involved in the maintenance of Habbo-retro websites. Several different versions of Habbo-retro websites exist, some which mimic the style of older versions of the "Habbo Hotel" game, while others follow the same design as the most up-to-date game.
Habbo-retro sites are typically maintained and run on server emulators for both hobby projects and profit-seeking endeavors. Some revenue models that are used include subscription fees and advertising on the website.
A server emulator is necessary because it allows Habbo-retro websites to bypass the encryption codes of legitimate "Habbo" software. Once compromised, the client software links to the emulated server rather than the official "Habbo" servers. Images and data used on an emulated server are illegal, as they are compromising the intellectual property of a product developed by Sulake.
While some Habbo-retro sites are safe to access, some are filled with viruses and trojans. Other retro sites may also steal user information through sign-up sheets for their versions of the "Habbo Hotel" game.
As of 2014, some existing Habbo-retro sites record up to 1,000 active users.