Club Penguin is an MMORPG involving a virtual world containing a range of online games and activities, developed by Club Penguin Entertainment (formerly New Horizon Interactive). Using cartoon penguins as avatars, players waddle around, chat, play minigames and participate in other activities with one another in a snow-covered virtual world. After beta-testing, Club Penguin was made available to the general public on October 24, 2005[1] and has since expanded into a large online community growing to the extent that by late 2007, it was claimed that Club Penguin had over 12 million user accounts.

While free memberships are available, revenue is predominantly raised through paid memberships which allow players to access a range of additional features, (such as the ability to purchase virtual clothing, furniture and "pets", also called puffles, for their penguins through the use of in-game currency). The success of Club Penguin led to New Horizon being purchased by The Walt Disney Company in August 2007 for the sum of $350 million, with an additional $350 million in bonuses should specific targets be met by 2009.

The game is designed for children between the ages of 6 and 14 years old.Thus a major focus of the developers has been on child safety, with a number of features introduced to the game to facilitate this — including offering an "Ultimate Safe Chat" mode, whereby users select their comments from a menu; filtering that prevents swearing and the revelation of personal information; and moderators (along with veteran players) who police the game. Nevertheless, the game has had a degree of criticism, including claims that it teaches consumerism and that some players "cheat" to improve their status.[

As part of Rocketsnail Games, Priebe released Experimental Penguins in 2000, which featured gameplay similar to that which was incorporated into Club Penguin. Although Experimental Penguins went off line in 2001, it was used as the inspiration for Penguin Chat, which was released shortly after Experimental Penguin`s removal. Thus, when Priebe, Merrifield and Krysko decided to go ahead with Club Penguin in 2003, they had Penguin Chat to inform part of the design process. After two years of testing and development, the first version of Club Penguin went live on October 24, 2005.

This project allowed players to be part of the testing of new servers put into use in Club Penguin on April 14, 2008.[15] Players had a "clone" of their penguin made, to test these new servers for bugs and glitches.